Thursday, 25 November 2021

WHAT'S THE DIFFERENCE BETWEEN A SPRING AND AN ARTESIAN

 People who live in the city do not have to worry about wells or springs. The city supplies them with water. But out in the country and in some suburbs. Obtaining a water supply may be quite a problem. Such water may come from a spring or a well. A spring is a water that flows from a natural opening in the ground during the rainfall, part of the WELL? Water soaks into the soil and rocks through small spaces and cracks and is pulled down by gravity as far as the openings in the rocks will allow At different levels below the surface of the land there is a zone where all the openings in the rocks are completely filled with water.

This is called "the underground zone". The upper surface of it is called the water table". In valleys or other low places in the land surface, below the water tables. Springs occur where there are cracks in the rocks. In other words, the water that has been stored up there escapes as spring water. Some springs flow all year because they receive water from deep within the ground-water zone. Other springs flow only in the rainy season when the water table is at its highest level. 

An artesian well is a well from which the water bubbles up naturally above the surface of the earth. An artesian well is formed when a layer of loose rock gravel or sand is sand between two layers of solid rock. The loose gravel or sand has spaces to hold the water. So we have three lavers-solid rocks above and below and a porous layer that is like a pipe between them. These three layers are not horizontal, they lie at an angle. Water enters the middle layer at the top end. Farther down, if an opening is made, there is a pressure that makes the water spurt out and we have an artesian well.

Monday, 1 November 2021

The British Magpies


One for sorrow, two for joy but what do you get for 100 or even 150 Magpies Pica pica? Groups of this size are not uncommon, and indeed the antics of large gatherings of Magpies were described by the Reverend Darwin Fox to his cousin, Charles Darwin, who subsequently wrote:

“The common magpie used to assemble from all parts of Delamere Forest, in order to celebrate the 'great magpie marriage'. They had the habit of assembling very early in the spring at particular spots, where they could be seen in flocks, chattering, sometimes fighting, bustling, and flying about the trees. The whole affair was evidently considered by the birds as one of the highest importance. Shortly after the meeting they all separated, and were then observed to be paired for the season.” (Darwin 1871)

The Magpie is a small-to-medium-sized member of the crow family (Corvidae).  The adult males weighed 248 g and adult females 223.3 g. The sexes are identical in plumage, but the size difference between the sexes is often apparent if they are seen side by side. The Magpie has a wide geographic distribution, breeding throughout most of Europe and Asia, North Africa, and western North America.

Geographic variation exists, generally in terms of body size and the relative amounts of black and white plumage. Inevitably, a species with such a broad geographic range occupies a wide range of habitats, from the semi-arid desert in North Africa, and the prairies of North America, to Alaska's boreal forests. In Britain, its habitat includes the lush farmland of lowland England and the windswept moors of the Peak District. The estimated breeding population of Magpies in Britain and Ireland to be about 250,000 to 500,000 pairs.

This is a resident population, and there is no immigration into Britain from the Continent. In Britain, the Magpie has undergone a population increase during the past 40-50 years. Therefore an increase has also resulted in the spread of Magpies into the urban areas.

This increase in abundance has been met with a variety of responses: obviously, Magpie enthusiasts have welcomed it, but they are pretty thin on the ground. The commonest response has been concern over song-bird populations (see page 598). Ringing recoveries show that Magpies rarely undertake long-distance movements. That the median distance between the natal nest and first-breeding location was just 447 m, equivalent to moving 1.8 territories.

As with other passerine species, females tended to move farther (497 m,) than males (350 m), although this difference was not statistically significant. The median distance between annual breeding attempts was even less: males 15 m and females 27 m. A significantly higher proportion of females bred in more than one territory during their life (13/48; 27%) than did males (5/ 64; 8%). This occurred because males which lost their partner were still able to defend their territory alone and invariably remained there.

In contrast, a lone female could not maintain a territory, so, if she lost her partner, she usually moved to another territory to repair. These results probably reflect Magpie dispersal fairly accurately; we regularly searched all surrounding areas for color-ringed birds, and, in ten years of enthusiastic Magpie recording by the Sheffield Bird Study Group, we had only four reported sightings of individuals more than 2 km from where they had been ringed. Magpies are monogamous, and a breeding pair defends an all-purpose territory.

In most studies of Magpies in Britain and the Continent, territories average about 5 ha in extent. The population can be divided into two sectors, the breeders and the non-breeders. In some areas, non-breeding individuals may comprise 20-40% of the total Magpie population.

Non-breeders are usually one-year-old and two-year-old birds (rarely three- and four-year-olds) that live as part of a loose flock ranging over the territories of established pairs. The flock is organized into a dominance hierarchy, with males generally being dominant over females.

This occurs partly as a result of the difference in body size between the sexes. The situation is rather more complex than this: the date that a young Magpie entered the non-breeding flock also had a marked effect on its status, with late arrivals achieving the lowest status. The pattern is by performing an ambitious experiment that involved hand-rearing and releasing 44 Magpies into the study area at different times. This result also explains why late-hatched young had the lowest likelihood of surviving to breed.

Providing that they survive long enough, Magpies start to breed in their first or second spring: mean ages of first breeding were for males 1.6 years and for females 1.4 years (this difference is not significant). Breeding Magpies in our study area (based on re-sightings of color-ringed birds) had a life expectancy of 2.0 (female) to 3.5 years (male).

The oldest Magpie we recorded died in its 9th year. However, the ringing recoveries provide a similar longevity record: 9.7 years. These data were obtained in an area where Magpies were unmolested; obviously, mortality rates will vary in different areas.

Diet and feeding behavior

Magpies are omnivores and will eat pretty well anything: we have seen them eat pears, dog faces with relish, attack a mole Talpa europaea, catch, kill and eat voles (Microtinae) as well as eating the berries of whitebeam, acorns, and household scraps.

It is difficult to build up an accurate picture of any species' diet because different study techniques have different biases associated with them. The stomach contents of shot Magpies and analyzed Magpie pellets and droppings. During summer, the bulk of the adult and nestling diet comprised grassland invertebrates (beetles, caterpillars, spiders, leather jackets, and earthworms). In winter, much more vegetable matter (e.g. seeds, bulbs) was eaten. A very little evidence that Magpies took many songbird eggs.

Like many other crows, Magpies hoard excess food. There is, however, not the slightest evidence that Magpies are specifically attracted to (or steal) bright objects such as money or rings. The food-hoarding behavior of the Magpies has some detail. Most food-hoarding by Magpies is short-term, with items recovered within just one or two days, unlike the Jay ‘Garrulus glandarius’ and nutcrackers Nucijraga, which cache acorns and pine seeds, respectively, in the autumn and eat them in the following breeding season. All but one of 3,184 caches by Magpies were made in the ground, usually in areas of short grass.

A Magpie typically filled its pouch with food, flew or walked to the cache site, and then made a hole in the ground with its bill. It then ejected the food into the hole and covered it with a stone, twig or piece of dead grass. We found caches extraordinarily difficult to relocate. On several occasions, we watched a Magpie hoarding food and maintained a fix on the hoarding place through a telescope while the other person walked into the field of view. This narrowed our searching area to about 0.2 m2, but we rarely found caches without a lot of trouble.

So how do Magpies relocate their caches? Although some experiments that Marmioc their sense of smell to find hidden food, they probably rely mainly on their well-developed spatial memory to relocate caches. We regularly saw Magpies fly directly to a point in their territory and recover cached food; unlike us, they found the food immediately, without having to dig up half the field. This strongly suggests that they could remember its precise location.

Squirrels and the Acorn Woodpecker store food in a single 'larder' which they then defend against other animals, but Magpies are 'scatter hoarders', dispersing their caches over a fairly wide area. Territorial Magpies hoarded within the territory and (by definition) non-breeders cached food within their home range, but these two categories of birds had different hoarding strategies.

Territorial Magpies made their caches much closer together than did non-breeding Magpie. To determine whether this spacing was adaptive, some field experiments; to test the idea that the difference in cache spacing was important in terms of the birds' likelihood of recovering them.

Grids of artificial caches at different densities were (laboriously) set out. Each cache, which consisted of 7.5 g of grain, had a two-pence piece placed under it, so that it could be relocated using a metal detector, but without providing any visual cues for Magpies. After four days, the grids were re-examined to record the proportion of caches still present. The experiment showed that the caches placed closest together suffered the greatest losses.

Subsequent observations showed that Magpies spaced their caches according to the rate at which the artificial caches had been lost in those same territories. In other words, the Magpies were able to assess the intensity of cache loss (probably through the number of other Magpies in the immediate vicinity) and space their caches accordingly. A territorial Magpie could afford to space its caches close together because no Magpies (other than its mate) were likely to enter the territory and raid the caches.

On the other hand, non-breeders generally foraged in a flock, and, once one Magpie discovered a food item (from a cache or otherwise), other flock members rapidly congregated in that area. In other words, if a non-breeder made its caches as close together as a territorial Magpie, it would almost certainly lose much of its hidden food to other flock members. By caching at a low density, flock Magpies reduced this risk.

Breeding biology

Nest-building may start very early; we have occasionally seen Magpies building on mild days in late December and early January, even though eggs are not laid until late March. Magpies may build a new nest or they may re-use or add to an old one. If a new nest is built, it is constructed in four distinct stages: an anchor, a superstructure, a mud bowl, and a lining. Once the Magpies have decided upon a nest site, the first place twigs there; these are followed by mud or clay, which forms the anchor.

Twigs are added to this to make the superstructure, including the domed roof. Once the superstructure nears completion, the mud bowl is started; and when this is finished the lining of hair and rootlets is added. Nest-building may be spread over two months, or a new nest may be knocked up in less than a week, Well-constructed nests are very durable and may last many years. One can tell quite a lot about the owners just by examining the nest.

One-year-old Magpies and first-time breeders generally build very poor nests—often not much better than bulky nests of Woodpigeon Columba palutnbus. In contrast, established breeders sometimes build fortress-like nests. One of our long-lived color-ringed birds built a particularly robust nest every year; the roof was especially dense, such that the nest contents were completely concealed from the outside.

Moreover, the roof was interlaced with spiky twigs of hawthorn Crataegus, making nest inspection particularly difficult for us. Most Magpie nests are roofed and found that 61 out of 79 nests (77%) were roofed and that 66% of those produced at least one chick, whereas only 5% of nests without a roof produced young.

Nests are built in a variety of locations, from the tops of 30-m beeches to scrubby willows Salix or hawthorns just a meter or so high. In some parts of the study area, Magpies had a wide choice of trees in which to nest; in others, at higher altitudes, there was little or no choice, since many territories contained only a single tree or bush. In treeless urban areas of Sheffield, we have found Magpie nests in British Rail watchtowers, on electricity pylons, and inside factories.

Egg-laying commenced in late March, and the annual median laying date (the date on which 50% of pairs had laid their first egg) varied from 10th to 24th April. Much of this variation was attributable to spring temperatures: in warmer springs, laying started earlier, and this, in turn, was almost certainly the result of warmer temperatures increasing the availability of the Magpie's invertebrate food.

Magpies are single-brooded, and the clutch consists of three to nine eggs; the mean number varied only slightly between years, from 5.5 to 6.3 eggs. Clutch size also varied within a season, with the earliest breeders generally producing the largest clutches. This in turn was a result of older Magpies breeding earlier and producing larger clutches than young Magpies.

If the first clutch is lost, a replacement will be laid, and, in our study area, almost always in a new nest. Replacement nests were always within the territory, but were often difficult to find, because, unlike first nests, they were usually built when the trees were in leaf. Magpies would lay up to four clutches in a season if necessary.

Incubation lasts for about 18 days and is undertaken entirely by the female. The male feeds the female on the nest, and the extent to which he does this helps to determine their likelihood of success. Females that are not looked after by their partners have to leave their eggs more often to feed themselves, and this increases the risks of the eggs being taken by predators.

There were two main causes of egg loss: small boys (which we cured of the habit rapidly) and Carrion Crows. Carrion Crows and Magpies are arch enemies; they compete for food and probably nest sites, and Carrion Crows will eat Magpie eggs or chicks at any opportunity. As a result, Magpies breeding close to a pair of Carrion Crows generally had relatively low breeding success. In one year, we estimated that over 30% of all Magpie breeding attempts failed as a result of Carrion Crow predation.

The Carrion Crow catches an adult Magpie in flight and kills it. Magpie nestlings leave the nest after about 24 days. We weighed, measured and color-ringed nestlings at 14 days after hatching; later than this and we would have risked them 'exploding' from the nest. After fledging, the young remain with their parents for about six weeks; in one or two cases (out of about 1,000) young Magpies stayed with their parents in the territory until the following breeding season. In our study, breeding success averaged about two nestlings per pair, although some pairs were very successful and raised large broods, whereas others failed to rear any young at all.

This is reflected in the lifetime reproductive success of Magpies: 60% of females and 40% of males failed to produce any young during their lives. During the course of our study, the Magpie population doubled, examined the effect of this increase in Magpie density on breeding success. Interestingly, there was no effect on either clutch size or breeding success, but there was a strong effect on juvenile survival.

The proportion of Magpies surviving through their first year was negatively (and significantly) correlated with breeding density. This indicates that density-dependent mortality of juvenile Magpies is one of the factors regulating Magpie populations.

Reproductive behavior

Many bird species, like the Magpie, traditionally regarded as monogamous, are now known to be less monogamous than once thought. The female’s trouble they went to protect their paternity. If similar things went on among birds: it soon became apparent that they did. Established pairs of Magpies live in their territories all year round, but the male and female may operate independently for much of the time.

From just before and during egg-laying, however, the male never lets the female out of his sight, remaining close beside her and following her every move. If she flies, he follows. If she walks behind a wall, he moves so he can still see her. Why should the male be so keen to keep close to his partner at this time?

The answer is that he is guarding her against the sexual advances of other males. Male Magpies are remarkably randy and regularly try to mate with neighboring females. On several occasions, we saw a male sneak (literally) into the adjacent territory, using the vegetation as cover, approach the female, and attempt to mate with her.

Most of these extra-pair copulation attempts were unsuccessful because they were cut short by the male partner chasing the intruding male. The closest that I saw a male come to being successful occurred when a guarding male fell asleep. His head lolled onto his breast, and, in so doing, fell below the top of the wall so that he could no longer see his female, who was foraging close by. Within a second or two of this happening, the male from the adjacent territory flew across and mounted the female. I think that local contact was not achieved; the female called during the mating attempt and this alerted her partner, who woke up and flew down and chased the other male and his partner.

This would be the end of the incident, but there was a further development. When this extra-pair copulation attempt occurred, the female had already laid part of her clutch, but her partner immediately started to build a new nest in a tree adjacent to the original nest. The female laid the rest of her clutch in the original nest but never started to incubate. Instead, she subsequently produced a repeat clutch in the new nest. The interpretation was that the male partner did not want to risk the fact that his female may have been fertilized by the other male. Hence, waste his effort by rearing chicks that may not have been his own.

Subsequent studies have shown that both mate-guarding and extra-pair copulations are widespread among many bird species and that such extra-pair mating can result in extra-pair paternity. Magpies showed some interesting extra-pair responses to a tame, caged female placed in their territory.

If the male approached the tame female alone he invariably courted and attempted to mount her. But if the pair approached the 'intruder' together, they were always aggressive towards her. Often the male would approach on his own and start to court the female, only to be followed a minute or two later by his partner.

As soon as he heard his female approaching, the male's courtship switched to aggression. The human analogy is obvious. It is perhaps surprising that we have actually seen as many, or probably more. The extra-pair mating attempts then have pair mating. The courtship between Magpies is infrequent. It consists of the male circling the female with his wings flapping and tail held high and twisted to one side. Mating is brief (1-2 seconds) and very rarely seen. On the basis of prolonged and detailed field observations, Magpies probably copulate only about three times for a clutch.

Groups and Territories

Magpies are regularly seen in groups, from half a dozen to over 100 birds, and these groups may occur for a variety of reasons: mobbing, feeding, roosting, and 'ceremonial purposes. Magpies may assemble to mob predators such as foxes, cats, weasels, rats, or owls, but mobbing groups are usually small (up to ten birds) and disintegrate fairly quickly.

Non-breeding Magpies live as members of a flock, but these flocks are very loose, and all members come together only if food is locally abundant (e.g. if muck has recently been spread in a field). In our study area, the Magpie population density was high; the largest feeding flocks that we saw consisted of about 50 birds, but feeding groups of 20-30 were not unusual. Groups also occur where territories abut, and the pairs perform parallel walks along their respective boundaries.

If the territory boundaries were unknown to the human observer, these birds would appear to be a 'group'. The largest groups occur at roosts or pre-roost gatherings, where over 100 may congregate. In our study, most Magpies roosted in small groups (of about 30 individuals) close to or within their daytime range, but, just 2 km away, a roost of 150-200 Magpies existed throughout the autumn and winter. These birds roosted in hawthorn bushes in an area of dense scrub, but they entered the bushes only just before dark. Prior to this, the birds assembled in a pre-roost gathering in a field some 200 m away.

The observations support the idea that Magpie communal roosts contain mainly non-breeding Magpies while established breeders roost singly or in pairs within their territory. The final category of the group is that about which Darwin wrote, now generally known as 'ceremonial gatherings'. These groups are rarely as large as pre-roost gatherings, although they have sometimes been depicted as such.

The average size of 225 ceremonial gatherings is to be nine Magpies (range 3-24). Gatherings occurred at all times of year but were most frequent during January to March (i.e. just before the breeding season). They also tended to occur more frequently in the morning than in the afternoon. The function of ceremonial gatherings has been discussed for a long time and suggested functions included pair formation and competition for nest sites or territories. Only through having individually color-marked birds of known status were we able to work out what was going on in these gatherings.

Initially, most gatherings that we observed were in progress when we first saw them, but we soon discovered that the key to understanding them was to see them from their inception. Gatherings were usually initiated by one or two non-breeding Magpies, usually the most dominant members of the non-breeding flock. Single initiators were always males, and 80% of groups of two were paired birds. Gatherings were started in the following way: the bird would fly unusually high and would then swoop directly down into occupied territory.

There they would instantly be met by the territory owners, who would call and chase them. This in turn would attract non-breeders in the vicinity and the holders of adjacent territories (only rarely did breeders 'leapfrog' territories to join a gathering). Almost all the 'action' during a gathering occurred between the initiators and the territory owners. The other birds were present as mere spectators. Sometimes, however, one of these would be accidentally drawn into the chasing and calling if it was attacked by mistake, resulting in the apparent 596

The Magpie chaos typical of these gatherings means the duration of gatherings was ten minutes and the maximum was 70 minutes. In most cases, the gathering soon subsided and the initiators left the territory, followed by the other individuals dispersing. What is happening is as follows. Competition for territories is intense. In our study area, all available space was occupied by territorial Magpies and a large pool of potential breeders (the non-breeding flock) existed. Instead of passively waiting for a vacancy to arise, say through a territory owner dying, the most dominant flock birds attempted to obtain a territory by force.

They visited territories in a deliberately provocative manner, confronting the owners in order to monitor the strength of their aggression. In most cases, the initiators quickly backed down and left, but, occasionally, they found a pair whose territory was less strongly defended. They then appeared to press home an attack, harassing the owners with repeated visits and prolonged chasing. In a few cases, the territory owners were evicted, in others, the gathering initiators carved out a very small piece of ground for themselves. If this occurred, it was usually at the junction of two or three territories (the point where the defense was weakest).

Once they had obtained a foothold there, the invaders gradually expanded the territory until, after a week or so, it was sufficiently large for breeding. We estimated that a third of the territories were obtained in this way. Evicted territory holders usually disappeared (which probably means they died) or became members of the non-breeding flock (which was genetically equivalent to being dead, for none of these birds ever bred again). Why did other Magpies turn up as spectators at gatherings? I think the reason is that it was in the interests of all nearby birds to know what was going on. A change in territory ownership could, through a domino effect, lead to a change in fortunes for these other birds as well.

A change in the ownership of one territory sometimes resulted in a succession of subsequent changes. There were two other ways in which Magpies could obtain territories:

(i)                 Replacement

(ii)               What we called 'squeezing in.

The replacement was straightforward: one or both members of a territorial pair died or disappeared and their places were taken by non-breeders, without a gathering.

Squeezing-in consisted of pairs taking advantage of the decline in territorial aggression that occurred after egg-laying. These birds simply squeezed in at the junctions of existing territories, without a gathering. Those that squeezed in, however, usually did so too late to breed in that season.

Bird and territory quality

The effect of bird and territory quality on reproductive success was examined in detail. This showed that some territories were occupied more (and others less) than expected by chance, a result that suggests that territories differed in their quality.

Furthermore, analysis of territory composition showed that the number of years in which the territory was occupied was positively (and significantly) correlated with the relative amount of grazing land (short grass with cattle or horses) in the territory. Several other lines of evidence indicate that this is a good measure of territory quality:

(i)                 Magpies obtain most of their food from such areas above.  

(ii)               The breeding success was positively correlated with the relative amount of grazing land in the territory. It is also found territory quality to be important in affecting the Magpie's breeding biology: his studies indicated that food availability determined the quality of a territory.

The importance of the experiment is by providing some Magpies with the additional food prior to egg-laying. Fed birds lay earlier, produced larger eggs and clutches, and reared more young than did unfed birds. In our study area, territory quality was obviously important, found that bird quality played a bigger part than territory quality in determining breeding success.

The disentangle the effects of territory and bird quality on breeding parameters (such as clutch size and laying date). That is by looking at these parameters when the same territories were occupied by different birds. However, these parameters for the same birds breed in different territories.

This analysis showed that about 60% of the variation in clutch size, egg size, and breeding success was attributable to bird-quality effects, whereas territory quality accounted for less than 10% of the variation in breeding success.

Magpies and song-birds

Magpies have been much in the news in Britain in recent years: their increasing abundance in urban and suburban areas has evoked some strong reactions regarding their possible effects on garden songbirds. Some city councils have even contemplated Magpie culls.

Also, the magpie killing and eating a young Blackbird “Turdus merula” while the Blackbird parents fly around frantically calling is not a pretty sight. But many of those who would happily shoot Magpies for such behavior tell of their excitement at seeing a Sparrow-hawk “Accipiter nisus” take a Starling “Sturnus vulgaris” from the bird-table.

Such double standards mean that there can be no grounds for condemning Magpies for the emotional trauma they cause bird-lovers. The real question must be whether Magpies take sufficient numbers of songbirds (adults, young, or eggs) to reduce their populations significantly. More research is required to resolve this. Though, there are several points that should be kept in mind:

(i)                 The results from the Common Birds Census (CBC) show that Magpie numbers have increased. Hence, they do not show a decrease in the numbers of Blackbirds, Song Thrushes “Turdus philomelos”, Dunnocks “Prunella modularis” or Collared Doves “Streptopelia decaocto”, are the main targets of Magpie attacks. The most CBC plots are in rural rather than suburban or urban areas, however, so we still need more information on this topic.

(ii)               The suburban song-bird populations exist at densities much greater than they do in traditional, woodland habitats;

(iii)              The ringing recoveries and other types of the study point out that the main predator of garden birds is the domestic cat. How many bird-lovers also own a cat? Virtually all the information which we have obtained on Magpies during the last few decades has been obtained through the use of color-marked individuals. These studies have been conducted primarily with rural Magpies. Hence, a similar investigation of Magpies in suburban and urban areas would provide an interesting comparison and would allow us to assess the impact of Magpies on songbirds. Clearly, we should reserve judgment on this issue until we have some hard facts.


 

Reference - British Birds VOLUME 8 2 NUMBER 12 DECEMBER 1989

 

Sunday, 31 October 2021

The scientific name of Moltoni’s Warbler

 Moltoni’s Warbler has been known either as subalpine and moltonii. The latter name,

given by Orlando in 1937, has been in wide use, but as Baccetti et al. (2007) pointed out

subalpine is valid and has priority. The Temminck type specimen of subalpina is reputedly

long since lost due to insect damage (fide Baccetti et al. 2007), and requests to the Leiden and

Paris museums have not changed that.

The type was described (Temminck 1820b) as a female, but based on Temminck’s plate

(see below), its lead-grey upperparts, and prominent pink underparts, I conclude that the

specimen was a male. According to Temminck, the type had ‘a beautiful vinaceous color’

below. The adjective used (Fr. ‘vineuse’, vinaceous) is the same that Ridgway (1912) used

for such a pink, and because males of all other Subalpine Warbler populations possess

more orange-brown or reddish underparts it is probable that Temminck was struck by the

unusual and attractive pink of male Moltoni’s Warbler when he described subalpina. In his

Pl. 6, no. 2, a painting of subalpine shows an adult bird with lead-grey crown and mantle

typical of males, and pink, not orange-red, underparts. Temminck specifically states that

the bird in the said plate was the only known specimen, sent to Temminck by Bonelli,

making it the holotype by monotypy. There can be no doubt that Temminck’s plate refers

to this taxon, making subalpine the oldest available valid name, with priority over moltonii

Orlando, 1937.

That the type locality ‘near Turin’ could fit not only Moltoni’s Warbler but theoretically

also Eastern Subalpine Warbler is of subordinate importance given the existence of

Temminck’s plate and Temminck’s (1820b) statement that the plate depicted the unique

specimen. Furthermore, it clearly shows the characteristic tail pattern of Moltoni’s Warbler,

with the square white tips to the penultimate feathers excluding Eastern Subalpine Warbler.

Temminck published information on his Sylvia subalpina twice in 1820. First (Temminck

1820a) was the plate in August 1820, along with a wrapper giving the scientific name of

this and other taxa depicted in the six plates comprising this part of the Planches coloriées

of Temminck & Laugier, wherein Baron Laugier took no part in naming taxa (cf. Dickinson

2001). The second was a description in the Manuel d’ornithologie (Temminck 1820b), published in

October 1820 (see item 3681 in the Bibliographie de la France, issue no. 43, of 21 October 1820).

Interestingly, Temminck (1824) depicted a perfectly identifiable Eastern Subalpine

Warbler, presumably subspecies albistriata, in Pl. 251. The contrast between the dark rufousred

breast and white belly is striking. In the text, the bird is labelled as the male Sylvia

subalpina. The painting was based on a bird collected by a Mr Heckel in Silesia, Poland,

near the German border (if correct, obviously a spring overshoot since the usual breeding

range today runs south of the Alps east to south Bulgaria and western Turkey, and is not

thought to have been substantially different then). However, Pl. 251 appeared four years

later than Pl. 6 and does not depict the type of subalpina, which name must be linked to the

bird on Pl. 61.

Sunday, 24 October 2021

Hummingbirds and Food Plants

 Hummingbirds and their food-plants rely to a large extent on each other for food supply and pollination service, respectively. This mutual relationship has co-evolved for millions of years and across the Americas involving over 330 hummingbird species and an estimated nearly 8000 plant species relying on hummingbirds as their principle pollinators.

Although birds other than hummingbirds also act as pollinators, hummingbird plant interactions are one of the most striking examples of bird-plant co-evolution, and the associated morphological adaptations have been studied intensively e.g, Snow.

 These studies have found that plants adapted to hummingbird pollination typically are odorless, have a long and narrow conspicuous orange-red tubular corolla, and produce extensive dilute nectar - broadly matching the sensory capabilities, morphology and energetic demands of hummingbirds. Similarly, hummingbirds show an array of features considered nectar-feeding adaptations, such as the capability to hover, a specialized tongue, highly specialized and variable bill morphologies, as well as a minute body size.

The smallest of all birds is the Bee Hummingbird (Mellisuga helenae) endemic to the Cuban archipelago, including the main island of Cuba and Isle of Youth (formerly Isle of Pines), in the West Indies. Of the 15 hummingbird species endemic to the West Indies, the Bee Hummingbird is the only species considered threatened on the IUCN red list.

Although the Bee Hummingbird is the smallest bird in the World, is categorized as Near Threatened and its population size is clearly declining, only very basic information regarding its distribution and reproduction has previously been reported. Almost nothing is known about its feeding ecology. For instance, apart from the record of some 15 food plants, nothing is reported about its preferred food plants or the overlap in flower use with the larger-sized Cuban Emerald (Chlorostilbon ricordii) - the only other resident Cuban hummingbird.

We here: 1) identify and describe the floral traits of several food plants the Bee Hummingbird uses; 2) report to what extent the Cuban Emerald uses the same flowers as the Bee Hummingbird; and 3) compare our data on flower use with those previously reported, and discuss how our results could direct future studies beneficial for the conservation of the Bee Hummingbird.

Each of the identified ten plant species visited by the Bee Hummingbird belongs to different plant families, of which one species (Antigonon leptopus) was introduced to Cuba. The remaining nine plant species are either native or endemic to Cuba (Table 1). Most of the ten flowers visited by the Bee Hummingbird - of which nine were also visited by the Cuban Emerald, as well as insects, such as bees and butterflies - have floral traits that fall outside the traditional ornithophilous syndrome, noticeably most flowers had little nectar and a short, white corolla, although some had more vivid colors.

This indicates that the Bee Hummingbird uses plants with generalized pollination systems as has also been reported for plants visited by small hummingbirds on Trinidad, Tobago, and other islands in the West Indies.

Conclusions. A total of 15 plant species from 15 different genera had previously been reported to be visited by the Bee Hummingbird, but no study had described their floral traits. Of the herein-reported ten food plants, only one species (Hamelia patens) occurs in the 15 genera previously listed as being visited by the Bee hummingbird. Many of the previously reported food plants in the Zapata Swamp were observed in March–June during the breeding season of the Bee Hummingbird, whereas the food plants we here report bloom in the latter part of July, outside the breeding season of the Bee Hummingbird.

In Cuba, the dry season extends from November to April, whereas the wettest months are from June to October (Garrido & Kirkconnell 2000). Therefore, it seems likely that the flower community largely changes between the dry and the rainy season, roughly coinciding with the termination of the Bee Hummingbirds breeding season.

This is the first step in identifying the floral niche of the Bee Hummingbird. We recommend that a quantitative field study be undertaken to evaluate the floral overlap in the context of floral use and availability, and behavioral interactions with the Cuban Emerald (Vaurie 1957) and insect-pollinators, such as the potential negative impact of the non-native honeybee (Apis mellifera). Comparing the herein reported food plants of the Bee Hummingbird with the plant species indicates that it would be essential to examine both dry season and rainy season floral overlap and behavior.

It would also be interesting to study the effect of introduced plants, forest loss, and degradation on the feeding behavior of the Bee Hummingbird. Finally, we recommend that field studies are also conducted in other areas than the Zapata Swamp, e.g., in the Bee Hummingbirds strongholds in the low-lying Guanahacabibes peninsula in western Cuba and in the eastern mountains of Cuchillas del Toa and Sierra Cristal. This should prove valuable for the conservation of the Bee hummingbird, an endemic and threatened species of the Cuban archipelago, West Indies. 


Tuesday, 19 October 2021

CURLY DOCK Rumex crispus

Curly-leaved dock, Yellow dock, Sour dock, Indian tobacco POLYGONACEAE

Buckwheat Family

SIZE = Plant: 2–4 feet, basal rosette is winter-hardy.

Flower: = 1/6 inch, in slender spikes. With 6 sepals, no petals.

LEAVES = 6–12 inches; with wavy, curled margins.

BLOOMS = March-May

At least fifteen Rumex species inhabit Texas and several ranges into the Houston area. While none has showy flowers, the docks are nevertheless conspicuous plants with interesting features. Curly dock, R. crispus, is the largest and most common of the local species. A native of Europe, this alien has become established in fields and disturbed ground throughout the United States. A stout perennial from a heavy taproot, it has a hardy rosette of leaves that remains green all winter, lining Houston roadsides even when other vegetation is withered and brown.

Curly dock is easily recognized by its long, slender leaves with crisped and wavy margins. The flowering stem reaches four feet, with tiny green flowers arranged on slender, branching spikes. There are six sepals in two ranks, but the flowers have no petals. Brown, heart-shaped, three-winged fruits fill the terminal spikes in late summer and fall.

While some authors regard curly dock as a “noxious weed,” natural-foods enthusiasts praise it as a rich source of vitamins A and C. Tull suggests using the young leaves as a substitute for spinach in salads or as cooked greens. Large doses, however, may cause gastric distress. Native Americans ground dock seeds and used the meal in bread, but Tull points out that removing the papery husks entails a great deal of work for a small amount of flour. Dormon also notes that the Chitimacha Indians of southern Louisiana used curly dock, which they called “deer’s-ears,” for dyeing their cane baskets.


Herbalists consider tea from the dried roots of the dock to be an excellent “blood purifier” and use it for a variety of skin diseases, rheumatism, liver ailments, and sore throats. It may either cause or relieve diarrhea, depending on the dosage, the season of the year, and the concentration of tannins and other chemicals in the plants.

Plain-tailed Warbling-finch

Plain-tailed Warbling-finch Poospiza alticola restricted to the high Andes of north-west Peru (Cajamarca to Ancash), this species inhabits shrubby forest and mixed Polylepis-Gynoxys woodland at 2,900-4,600 m. It seems to favor ravines, but it is scarce even in optimum habitat. High-altitude woodlands are now highly fragmented and further habitat loss and degradation are predicted. The main causes are cutting for firewood and a lack of regeneration due to burning and overgrazing. Other threats include the change from camelid to sheep and cattle farming, erosion and soil degradation caused by agricultural intensification, road construction, and afforestation with exotic tree species. Although it occurs in Huascarán National Park (Ancash), habitat degradation continues. The estimated population is around 500 to 1600 birds.


Thursday, 30 September 2021

How Water Change the Lands

Water means life. Without water we, along with the plants and animals we depend on, all die. Water covers 70% of the Earth’s surface. Water is the creator of life, but it is also the destroyer. Drownings, flooding, tsunamis, and drought (a lack of water) claim thousands of lives each year. That makes water the perfect subject for myths. Water seeks low ground, always flowing downhill, rushing, tumbling, roaring to get lower toward sea level. Streams, rivers, and creeks swirl, gurgle, tumble and flow across the landscape. These waterways are always tucked along the bottom of gullies, valleys, and canyons. Waterways are never found riding a ridgeline or marching across the crest of a hill. 

Most origin myths begin with water (oceans) and the heavens already in existence. From these, some being forms land and creates life. Literally, hundreds of creation myths begin by saying that in the beginning, the world was all water. In myths, water usually affects the land (once land exists) only as a flood. Myths from hundreds of traditional cultures talk about the great flood that scoured the landscape, wiped out early evil or unjust civilizations, and gave humanity a second chance. Even landlocked cultures in arid regions the Sioux and Arapaho tribes, for example, have myths of a great flood that covers the Earth and kills almost all living beings. 

The biblical flood of Noah is one of the few foods that can be traced to a specific geologic cause and event. Most exist in mythology even though there is little evidence that they ever happened in physical reality. Water is also the source of fog and mist—creepy earthly shrouds that seem to invite mystery, supernatural events, or the arrival of evil. The action of water, especially acidic waters, creates caves and caverns. These empty spaces in the Earth’s mass have always been viewed as dark and mysterious places. 

Caverns are doorways to the underworld and to the land beyond death. To many people, it seemed wrong and unsettling that solid Earth should have such holes and gaps as if caves represented a mistake or the work of a demon. Certainly, water deeply affects even controls life. But does water affect the land itself? Earth Scientists study the land, not the life upon the land and certainly not the marine environment. Does water alter land? Is our land different because of the action of water or the presence of water? 

Does a study of the land require a study of water and the water cycle? A few creation myths try to explain the origin of the oceans and of water. Virtually none, however, focuses on the effect of water on the land, on how water changes the land. Water creation stories typically rely on the mischief, greed, or misdeeds of a character to trigger catastrophic events that create the sea in a great flood. In one especially inventive story from Thailand, villagers decide to build bigger and bigger kites to win a kite-flying tournament. 

A clever man, helped by a gang of children, builds a kite bigger than houses, bigger than fields, bigger than valleys. A great storm blows in and lifts this enormous kite. The man and the children try to hold on, clutching at trees, grass, rocks, and even the ground itself. But the storm lifts the kite high into the sky, pulling people and a great chunk of the Earth with it. The hole left behind forms the Bay of Siam. The bay fills with water that bubbles up from below, and the water spills over to create the oceans. The chunk of Earth flies up to become the moon. 

The kite sails even higher to become a constellation of stars in the twinkling night sky. In a myth of the Tiano people of the Caribbean Islands, a famous hunter is killed by a hurricane. His magical bow is placed in a calabash and, when his people are in desperate need, this calabash splashes out fresh fish. Greedy boys break the calabash, and out-pour all the waters of the oceans and seas. In a Venezuelan myth, the sea is trapped in a greedy pelican’s egg. The pelican wanted to hoard all the fish for itself. 

A curious and mischievous boy cracked open the egg and out spilled the ocean to cover everything except the mountaintops that became islands. Water means life. Without water we, along with the plants and animals we depend on, all die. Water covers 70% of the Earth’s surface. Water is the creator of life, but it is also the destroyer. Drownings, flooding, tsunamis, and drought (a lack of water) claim thousands of lives each year. 

That makes water the perfect subject for myths. Water seeks low ground, always flowing downhill, rushing, tumbling, roaring to get lower toward sea level. Streams, rivers, and creeks swirl, gurgle, tumble and flow across the landscape. These waterways are always tucked along the bottom of gullies, valleys, and canyons. Waterways are never found riding a ridgeline or marching across the crest of a hill. Most origin myths begin with water (oceans) and the heavens already in existence. From these, some being forms land and creates life. 

Literally, hundreds of creation myths begin by saying that in the beginning, the world was all water. In myths, water usually affects the land (once land exists) only as a flood. Myths from hundreds of traditional cultures talk about the great flood that scoured the landscape, wiped out early evil or unjust civilizations, and gave humanity a second chance. Even landlocked cultures in arid regions—the Sioux and Arapaho tribes, for example have myths of a great flood that covers the Earth and kills almost all living beings. The biblical flood of Noah is one of the few foods that can be traced to a specific geologic cause and event. 

Most exist in mythology even though there is little evidence that they ever happened in physical reality. Water is also the source of fog and mist creepy earthly shrouds that seem to invite mystery, supernatural events, or the arrival of evil. The action of water, especially acidic waters, creates caves and caverns. These empty spaces in the Earth’s mass have always been viewed as dark and mysterious places. Caverns are doorways to the underworld and to the land beyond death. 

To many people, it seemed wrong and unsettling that solid Earth should have such holes and gaps as if caves represented a mistake or the work of a demon. Certainly, water deeply affects even controls life. But does water affect the land itself? Earth Scientists study the land, not the life upon the land and certainly not the marine environment. Does water alter land? Is our land different because of the action of water or the presence of water? Does a study of the land require a study of water and the water cycle? 

A few creation myths try to explain the origin of the oceans and of water. Virtually none, however, focuses on the effect of water on the land, on how water changes the land. Water creation stories typically rely on the mischief, greed, or misdeeds of a character to trigger catastrophic events that create the sea in a great flood. In one especially inventive story from Thailand, villagers decide to build bigger and bigger kites to win a kite-flying tournament. 

A clever man, helped by a gang of children, builds a kite bigger than houses, bigger than fields, bigger than valleys. A great storm blows in and lifts this enormous kite. The man and the children try to hold on, clutching at trees, grass, rocks, and even the ground itself. But the storm lifts the kite high into the sky, pulling people and a great chunk of the Earth with it. The hole left behind forms the Bay of Siam. 

The bay fills with water that bubbles up from below, and the water spills over to create the oceans. The chunk of Earth flies up to become the moon. The kite sails even higher to become a constellation of stars in the twinkling night sky. In a myth of the Tiano people of the Caribbean Islands, a famous hunter is killed by a hurricane. His magical bow is placed in a calabash and, when his people are in desperate need, this calabash splashes out fresh fish. 

Greedy boys break the calabash, and out pour all the waters of the oceans and seas. In a Venezuelan myth, the sea is trapped in a greedy pelican’s egg. The pelican wanted to hoard all the fish for itself. A curious and mischievous boy cracked open the egg and out spilled the ocean to cover everything except the mountaintops that became islands.


Wednesday, 29 September 2021

Buff-tailed Sicklebill

As its name implies, the most distinctive characteristics of the Buff-tipped Sicklebill are its extreme bill shape and pale cinnamon-buff outer tail feathers with white tips. The sexes are very similar, but young birds can easily be distinguished from adults by pale feather edges on the wings and smaller patches of blue iridescence at the nape. The two subspecies are also very similar, but subsp. gracilis has a less heavily streaked belly and shorter bill than the nominate. 

Sicklebills have relatively short wings for such large hummingbirds, which reduces their flight efficiency and explains their tendency to perch rather than hover when feeding at flowers. Their long tails bob almost constantly, even at rest. In the narrow zone of overlap between the two sicklebill species, the Buff-tailed seems to prefer more open and disturbed habitats than the Whitetipped Sicklebill. Its nest is similar to that of the White-tipped, comprising a loosely woven cup secured with spider silk to the underside of a large leaf.

DISTRIBUTION Subsp. condamini occurs in the eastern Andes of southeastern Colombia, Ecuador, and northern Peru; subsp. gracilis occurs in the eastern Andes of Peru and northwestern Bolivia

HABITAT Undergrowth, wooded ravines, and stream sides in humid forest, swampy forest, bamboo groves, edges, overgrown clearings, plantations; 600–10,850 ft (180–3,300 m)

SIZE Length: 51⁄8–57⁄8 in (13–15 cm).

Weight: 8–12.5 g

STATUS Least Concern


Friday, 17 September 2021

MASKED TITYRA - A Little White Bird

In appearance, voice, and mannerisms, this medium-sized cotinga has a character all its own. At the first glimpse of a male Masked Tityra flying overhead, one is likely to exclaim, “A little white bird!” Closer scrutiny of the tityra reveals that his plumage is not so white as it first appears; a formal description of this stout, eight-inch bird fails to give an adequate notion of its whiteness when viewed in flight or as it rests in a treetop. His upper plumage is generally pale bluish-gray, becoming almost white on the hind head, and his under plumage approaches still more closely to white. His wings are largely black. 

The tail is pale gray with a broad, black subterminal band and a narrow whitish border across the end. His reddish eyes are surrounded by a broad area of bright red bare skin, which covers the lores. This naked patch is margined all around by black feathers, which form a narrow fringe across the chin and broadband over the forehead. The short, stout bill, of which the upper mandible is terminated by a short, down-curved hook, is red basally and black at the tip. The female tityra is far less white than the male, for her plumage is grayish-brown above and light gray below. The naked skin around her eyes is a paler red than that of the male. The legs and feet of both sexes are dark gray.

The species ranges from northern Mexico to western Ecuador, Bolivia, Brazil, and the Guianas. Over much of this vast area, it is one of the first members of the cotinga family that a visiting naturalist is likely to meet. Tolerant of varied ecological conditions, it lives not only in the most humid rain forests but also in semi-arid regions with scattered trees. In Central America, it is widespread over the lowlands of both coasts, and it extends far upward into the mountains. On the Pacific side of the Cordillera de Talamanca, I found it in late February nearly 7000 feet above sea level, and on the Cordillera Central in May I saw a wandering male at about 7500 feet, but I doubt whether tityras nest so high. At Vara Blanca on the northern side of the Cordillera Central of Costa Rica, I found it nesting at an altitude of 5.500 feet.

But in this extremely wet region I failed to see a tityra between August and late February, whence I inferred that it performs a slight altitudinal migration, dropping down to lower levels after the close of the nesting season and ascending the mountains again as the following breeding season approaches. Tityras are at home in the tops of the big forest trees, where one hears them far more often than he sees them. But they often make excursions, in pairs or small flocks, through clearings and plantations with scattered tall trees, and they often nest in dead trees standing isolated near the forest’s edge. Almost always they fly and forage at a good height above the ground. Except while nesting, these restless, wandering birds seldom remain long in one locality.

They appear to be mated throughout the year, for I have often seen pairs even in the autumn months. Yet at all seasons, including that in which they nest, one occasionally meets small, wandering flocks composed largely of males. The latter seems to be considerably more numerous than the females. After pairing, the male tityra is ever a faithful companion of his mate and seems subservient to her will. For example, late one cloudy afternoon in March, I noticed a pair of these birds resting in dead trees in a clearing beside the woodland, where they were preparing to nest. The male, which seemed eager to go to roost in the neighboring forest, flew twice across the clearing to a tree at its edge, where he called and waited for his partner to follow.

Since she was not yet ready to go, he returned each time to await her pleasure. Soon, however, she yielded to his entreaties, and the two flew away over the forest together. Like other cotingas, tityras, while perching, quietly turn their heads from side to side, scrutinizing the surrounding foliage until they detect an edible insect, which they snatch from the leaves by means of a sudden dart, without alighting beside it. The first tityra that I ever saw held in its bill a fleet-winged dragonfly, but I do not know whether this insect was captured while it was flying or at rest. Tityras also eat berries and other small fruits of trees. tityras went to rest much earlier in the evening and became active far later in the morning than many of the surrounding birds.


Nest Building

The Masked Tityra nearly always nests in cavities in dead or, more rarely, living trees, usually from 40 to 100 feet above the ground. Until quite recently, the lowest hole into which I had seen a tityra carry material was 20 feet up in a slender stub standing in a clearing, but apparently, she did not lay there. In 1964, however, a tityra built a nest in an old woodpecker hole only 13 feet up in the top of a small, dead avocado tree in a coffee plantation on our farm. I do not know whether she laid in this exceptionally low nest, as I left for fieldwork elsewhere. On the same farm in the following year, a pair of tityras raised a brood in a hole carved by Red-crowned Woodpeckers only 11 feet up in a slender stub, decayed, riddled by insects, and partly consumed by fire, that stood in an area where second-growth woods had been recently felled and burned for planting maize.

When the tityras took possession of this low nest site it was quite exposed, but by the time the eggs hatched it was barely above the tassels of the tall maize plants that surrounded it on all sides for 100 feet or more. Either cavity resulting from decay or those made by woodpeckers are acceptable to the tityras. The latter seems to be preferred, especially the chambers carved by species of Centurus, Tripsurus, and another medium-size woodpeckers, the doorways of which are barely wide enough to admit the tityra.

Tityras not infrequently capture holes still used by the woodpeckers for sleeping, or even those newly completed for the accommodation of the woodpeckers’  eggs and nestlings, evicting the hole-carvers by persistence rather than by violence, in a manner which we shall consider later. I have not known them to oust the woodpeckers from holes that held eggs or young. Long before the approach of the breeding season, the tityras, roaming in pairs through the forest and adjacent clearings, begin to examine woodpeckers’  holes and other cavities in trees which might later serve as nest sites.

I have watched them pursue these investigations as early as November; indeed, at all times of the year, they display curiosity about the holes in trees that they encounter on their wanderings. The female goes to the doorway of the cavity and looks in, while her mate, who follows her like a shadow, clings to a neighboring part of the trunk, his black-and-white wings half-spread. The male often goes to the doorway, too, after his partner has completed her inspection.

It is usually not until a later date that the birds enter the holes. At times it appears that the examination of potential nest sites may be made before the pair has been formed, or at least before the rivals of the successful male have become discouraged and abandoned their suit. On February 20, 1938, I saw tityras at Vara Blanca for the first time in half a year. On the following morning, I found several of these birds in a narrow clearing in the forest 5300 feet above sea level, where a pair had nested in the preceding July. While a female flew from one to another of the dead trunks standing in the pasture, looking into the many old holes that they contained, three males followed her, sometimes peering into the cavities, too. They voiced low notes, flitted their banded tails fanwise, and sometimes one flew toward another.

But the the individual so approached always retreated promptly, and there was no fighting, nor any suggestion thereof. After the female had made the rounds of the decaying trunks, she flew down the mountain, followed by her three suitors. This observation suggests that the tityra’s method of mating and establishing a the breeding territory is very different from that of finches and many other songbirds, in which the male settles in an area, advertises his presence by singing, and awaits the arrival of a mate.

The female tityra appeared to select the territory while the males followed her about, awaiting her decision. As late as March 6, there were three tityras in this clearing, but by the following day, another of the males had been eliminated. The female’s choice of a partner seemed to have been definitely made, but she has not seen building until April 3. At lower altitudes of 2000 to 3000 feet in Costa Rica, I have known the tityra

o begin building as early as the end of February, at the height of the dry season. March and April are the months of greatest activity in nest building. Pairs saw nest building as late as May are probably preparing for second broods or replacing nests that have been destroyed. Like many other birds, the tityras, especially the female, may gather material some time before they actually begin to build, carry it in their bills awhile and then drop it to the ground. In 1937, a pair of tityras was much interested in the still-occupied dormitory of a pair of Golden-naped Woodpeckers.

I first saw the female tityra with the material in her bill on February 20, but it was March 2 before I witnessed her taking anything into the hole that she had chosen for her nest. Yet two days later she perched motionless near this cavity with a billful of leaves, which she dropped after 12 minutes. While the female tityra was gradually working herself up to the point of beginning to build, her mate seemed impatient to have her proceed with the under- taking. Often, while she paused irresolutely in a neighboring tree, holding a twig let or dead leaf in her bill, he went to cling at the doorway of the woodpeckers’  hole, at times flying off a little way and then returning, as though to encourage her to take the stuff inside. Even when she was beyond sight, he might go to look into the prospective nest cavity, at times in the warmest hours of the afternoon.

For the tityra, nest building is a simple undertaking that requires no art. It consists merely of filling the bottom of the chosen cavity with a loose litter of small dead leaves, or pieces an inch or two long torn from larger ones, fine dry inflorescences of trees, thin twiglets, and rarely a small green leaf. This is done chiefly or wholly by the female, who gathers her material in the treetops, often at a distance from the hole, rather than from the ground, to which adult tityras never seem to descend unless drawn by a fledgling which rests there.

As a rule, she works in a desultory fashion, taking a few billfuls into the hole, then flying off and remaining away until one grows tired of waiting for her return. The male faithfully follows his building partner back and forth, often holding a leaf or twig, which after being carried on a number of trips is finally dropped some- where usually not into the nest. He sometimes takes material to the doorway, both while his mate is building and in her absence. He may do this repeatedly, seeming thereby to express his eagerness to have the female resume her task. The leaf or twig taken to the orifice by the male is often carried away again, and I have seen this happen four times in succession. Often the male drops his material while he clings in front of the doorway.

Nearly always it flutters to the ground, but some- times, that might say by accident, he pushes the leaf or twig far enough inside for it to remain when he releases it. His ineffectual efforts to help his mate in the building are amusing to watch and remind one of the equally unproductive preoccupations with the nest material of the male Black-crowned Tityra.

THE EGGS

The tityras’  nests which are placed high in dead trees of uncertain stability cannot be reached without great difficulty and danger. For many years, the only one that I could examine was about 3.5 feet up in a massive trunk standing in Gatun Lake, about 100 yards from the shore. This tree had been killed about 20 years earlier, when in the construction of the Panama Canal the lake was formed by impounding the waters of the Rio Chagres, and the wood was far advanced in decay. Great chunks of the tree fell off as we threw a cord across the truncate top in order to draw up a rope attached to a rope ladder.

I should never have climbed such a trunk if it stood on solid ground, but a fall into the water seemed less dangerous. In the upper side of a short stub of an ascending thick branch, at the very top of the trunk, I found an irregular hollow, doubtless made by decay, a foot deep and wide enough to admit my hand. Although the cavity opened upward, it slanted down into the wood, so that it gave the tityra protection from both the sun and the direct impact of rain.

When I peered in, I saw no eggs on the loose litter of leaves that filled the bottom of the cavity, but I could feel two eggs under the leaves. These eggs were dark buff or cafe’  au hit in color, heavily marbled, especially on the larger end, with brown. A few small, black spots were scattered over the surface. They measured 30.2 by 20.6 and 29.8 by 21.4 mm. At the low nest to which I gave much attention in 196.5, I could not see the eggs. This nest had an entrance too small to admit my hand, and to have made a larger opening would have endangered the contents. On 15 inspections with a mirror during incubation, I never glimpsed even part of an egg, as all were always completely covered by the leaf litter that filled the bottom of the cavity.

It was the same whether the female had left the nest spontaneously or flew out when she heard me approaching. Apparently, however, this nest also contained only two eggs, for this was the number of nestlings present, and no unhatched egg remained in the litter after the young fledged. Incubation began in this nest in El General at the end of May 1965. At the nest in the Canal Zone, incubation had already started by May 28, 1935. Both were probably second brood or replacement nests. I have no evidence of more than two broods per season in this species

Incubations

Only the female incubates. Often a number of days elapse between the end of the sustained building and the beginning of steady incubation, and in this interval, the female brings occasional billfuls of dry leaves to the nest. Her vacillating behavior in this period is most confusing to the watcher who cannot learn by direct inspection what the hole contains. Sometimes the female is seen looking out of her high doorway, from which at times she darts forth as though to fly away, only to turn after she has gone a few inches and re-enter it. Her mate may remain perched in a neighboring tree, from time to time going to the doorway to look in at her.

As the day ends, the female, often in company with her partner, lingers near the nest cavity, guarding it, but in the waning light both fly off together to sleep in the neighboring forest. After a few more days, the male departs first in the evening, leaving the female perching alone near the nest. As the twilight deepens, she may fly toward the doorway, only to turn back when in front of it, often repeating this move a number of times, but in the end, losing courage or changing her mind, and winging away through the dusk in search of her mate.

Such vacillation is especially likely to be noticed if, as often happens, a family of great-billed aracari toucans sleeps in a neighboring hole. At daybreak, before woodpeckers have emerged from their dormitories, the male and female tityras often fly together from the adjoining forest to perch for a while near their nest. From a cayuco moored to a neighboring stub, I watched the nest in Gattin Lake from 6:00 to 11:23 a.m. on May 29 and from 2:00 to 6:45 p.m. on the following day. In these ten hours, the female tityra took eight sessions on her eggs, ranging from 24 to 49 minutes and averaging 37.1 minutes. Her nine recessed varied in length from 13 to 29 minutes and averaged 19.6 minutes. She was in her nest only 65.4 percent of the observation periods, which is a poor record for so large a bird but is matched by that of the Black-crowned Tityra.

When she left her eggs, the tityra would emerge from the cavity and hop along the broad top of the stump to its highest point, where she usually stood for several minutes, preening her feathers, stretching her wings, or idly looking around, before she flew toward the land. It was remarkable how often her mate, watching from the neighboring forest, saw her before she reached the shore. Sometimes he advanced a short distance over the water to meet her, then together they vanished over the treetops. On five of her ten returns to the nest, the male escorted his partner to the stub standing in the water.

After resting for a minute or more atop the trunk near the doorway, he would fly back to the land, while his mate hopped down into the cavity. Once, as she was returning alone to the nest, the female tityra was attacked above the water by one of the Streaked Flycatchers which was feeding nestlings in a hole lower in the same trunk. The flycatcher plucked at the tityra’s feathers, causing her to cry out in alarm or pain. But as soon as she alighted on the stub, the flycatcher desisted from its attack.

The tityra promptly returned to the shore, as though for consolation from her mate, who a minute later saw her safely back to her nest. On another occasion, one of the flycatchers darted at the male tityra while he rested on top of the stub near his mate’s nest, causing him to retreat to the shore. But aside from these two incidents, the tityras, the Streaked Flycatchers, and the Palm Tanagers nesting in this stub dwelt in peace. The Blue-headed Parrots, whose two large but still naked nestlings rested in a large cavity below the tityras’  nest, remained out of sight the whole time that I watched.

From time to time, the female tityra toot a billful of leaves into the hole when she returned to resume incubation. I have seen other female tityras do the same. I climbed the rope ladder twice more, and each time I found the eggs completely buried in the litter. It was impossible to learn whether the tityra deliberately covered them as she departed or whether the leaves simply flowed over the eggs when she rose from the depression which she doubtless made in the loose mass while she sat. It is probable that the protectively colored eggs often escape predators by being covered with leaves in the bottom of a dark cavity.

In the middle of the afternoon, while the female tityra stood on the top of the trunk beside her nest, preening her feathers, her mate came bearing a big, green caterpillar and alighted close beside her. Without offering the food to her, he hopped to the rim of the nest cavity and looked down into it. Evidently, he had brought the caterpillar in expectation of finding nestlings to receive it, and when he learned that the eggs were still unhatched, he swallowed it himself. The male tityra not infrequently brings food to the nest in this anticipatory fashion, finds that there are still no young mouths to take it, then eats it himself or carries it away.

At another nest, I saw the male do this twice. Since, even while the two are attending nestlings, the male tityra does not pass food to his mate, these morsels are obviously not for her. Similar anticipatory food bringing has been witnessed at nests of a number of other passerine birds, especially those of wood-warblers and tanagers. It serves to form in the male parent, when he does not incubate, the habit of bringing food to the nest in advance of the hatching of the nestlings, with the result that after the young are hatched he will promptly find and attend them.

Seated on a log amid the maize plants which partly screened me, I watched the low nest in the milpa from 5:20 to 11:36 a.m. on June 5, and from noon to 5:40 p.m. on June 7. In nearly 12 hours, this tityra took 14 sessions on her eggs, ranging from 4 to 81 minutes in length and averaging 2 1.6 minutes. An equal number of recesses varied from 10 to 26 minutes and averaged 17.1 minutes. She spent only 55.7 percent of her active day on the nest, but this day was short. It began at 5:23 am on June 5, when the tityra left her nest in the cloudy dawn. Until 2:23 p.m. on June 7, she had come and gone very frequently, taking no session longer than 26 minutes. After her return to the nest at 2:23, the sky became darkly over-cast and intermittent sprinkles fell, hardly enough to wet the foliage.

The tityra now stayed in her nest continuously for 81 minutes. When finally she emerged at 3:44 p.m., it was only to rest in a neighboring dead tree, preening, scratching, and stretching her wings, until her return to her eggs at 4:02. Then she remained within continuously, never even showing herself in the doorway until I left when daylight was waning at 5:40 p.m. From 2:23 p.m. until nightfall, this tityra took no food.

In comparing the incubation records of the two tityras, it should be noticed that the Canal Zone, where the first nested, is only about four degrees east of El General, where the second nested, yet the first locality uses standard time for the seventy-fifth meridian and the second that for the ninetieth meridian, and their clocks are accordingly an hour apart. Hence the sun rises and sets, by the clock, much earlier in Costa Rica than in Panama. The tityra in the cornfield could barely squeeze through the round doorway of her nest hole that the woodpeckers had made.

She seemed to have little difficulty finding enough food in the neighboring forest where she foraged, for some times, even early in the morning, she would spend part or even the whole of her recess preening in a neighboring dead tree, often in company with her mate. He was attentive to her, and as she returned to her eggs he would often fly down with her, to rest atop the low stub while she entered the opening in its side. Once he clung before the doorway and pushed a piece of the dead leaf through it. Sometimes the female carried pieces of dead leaf in her bill when she went to resume incubation. This female was found in her nest late in the afternoon of May 29, and again on the following afternoon. Incubation had apparently begun by the former date.

One of the unseen eggs had hatched by 7:20 am on June 19, and the second egg no later than the next morning, after an incubation period of about 21 days. THE NESTLINGS Hatching and the beginning of feeding.-Bracing the back of the rotten stub in the cornfield and setting my ladder almost upright against the front, I climbed up and looked into the nest hole with electric light and mirror, at 7:20 a.m. on June 19. 

Now for the first time, I saw part of an egg-half of an empty shell. Its dark color made it difficult to distinguish from the leaves among which it rested. I heard peeps and from time to time saw the leaves move, but I could catch no glimpse of the newly hatched nestling(s) hidden beneath them. Both parents were resting in a dead tree at the edge of the field. Presently the male flew away and his mate fo8110wed. At 8:Ol she returned and entered the nest with a dead leaf in her bill, while the male rested on top of the stub. She brooded for 40 minutes, then left carrying a piece of eggshell.

When she returned 11 minutes later, she again held fragments of leaf, which she dropped while standing on the end of the stub before she entered. Now she brooded for 18 minutes, was absent for 19 minutes, and on returning at 9:29 she held a small green object that was evidently an insect, the nestling’s first meal. After another spell of brooding and another excursion, she again returned with a billful of leaf fragments which, before approaching the nest, she dropped while perching in a dead tree at the side of the field. Then she flew back to the forest, evidently for more food. Returning, she entered the hole so swiftly that I could not see whether she had brought anything.

But apparently, she fed the nestling, for she remained with her head down and her tail sticking up in the top of the hole for about a minute. At 1054 the male and female returned together and clung side by side to the top of the nest stub. The female had food in her bill. While she delivered it with her tail pointing upward at the top of the nest cavity, her mate looked in through the doorway. He returned to the top of the stub, but a few minutes later he again went to peer inside while clinging in front. Thereupon the female left, but he remained clinging to the stub for about a minute more before he followed her.

He evidently had intimations that some important change had occurred in the nest, for now, he spent more time on the stub than he had formerly done. Once more he looked in while his mate fed the nestling. Finally, at 11:42, he flew from the dead tree directly to the doorway with a small piece of food in his bill, entered, stayed in for about a minute, and emerged with empty bill. He first fed the nestling two hours and 13 minutes after the female did, and four hours and 22 minutes after I found the empty eggshell and heard the nestling peep. By noon, he had fed the newly hatched young twice; the female had brought food five or six times. When I looked into the nest at 8:00 the next morning, I could see parts of two nestlings. One promptly disappeared beneath the leaves, but most of the other, except its head, became visible when it shifted its position.

The few tufts of fairly long, light gray down that it bore on its head, wings, and back were far too sparse to cover its pink skin. I could not induce it to gape. This was the most adequate view that I was to have of a nestling for many days. For the next two weeks, they were always beneath the leaves, with rarely ahead exposed, whenever I looked into the nest. Brooding.-Perhaps because they were embedded in dry leaves in a snug nursery, these nestlings were brooded little.

During five hours of the morning of June 25, when they were about six days old, their mother brooded them only three times, for 28, 12, then 14 minutes. When 12 days old and still practically naked, the nestlings were not brooded at all during the first five hours of the morning. 

Feeding.-The number of meals delivered by both parents on six mornings is recorded in table 1. As far as seen, each meal consisted of a single item. Until the nestlings were over 24 days old, there was no significant increase in the rate of feeding, but after the first week, the parents rather consistently brought articles that were noticeably larger than those which newly hatched nestlings had received. Rarely they offered the nestlings an insect so big that it was swallowed with difficulty, or not at all.

This regimen of few but substantial meals was followed until a few days before the young left the nest when feedings became twice as numerous as they had been through most of the nestling period but the articles of food were often small. In 30 hours of watching, the number of meals received by the two nestlings in a single hour varied from 0 to 11; they were fed a total of 93 times, or at the rate of about 1.5 meals per hour for each of them. The nestlings’  diet consisted chiefly of insects, especially orthopterans.

The green color and massive bodies of many of these insects suggested that they had not been caught in the air but had been snatched from foliage, where their protective coloration had failed to conceal them from the tityras’  sharp eyes. Sometimes a brown or dark-colored insect was brought, once a large orange-tawny butterfly, and twice I detected a large spider in the male’s bill. Occasionally a small land snail was taken to the nestlings, as I learned when I found three small shells in the litter in the bottom of the nest after the young had flown. At other nests, I saw the parents bring caterpillars, and rarely a small lizard.

No fruits were detected in the parents’  bills when the nestlings in the cornfield were six days old, but when they were 12 days old they received a few. The rather large, green, olive-shaped fruit of a lauraceous tree was the kind most often brought. Each contained a single big seed surrounded by hard, thin flesh. After this had been digested away, the young birds regurgitated the seeds, of which I later found many among the leaves in the bottom of the nest. Each seed was from 3/a to 7/s inch long and about % inch thick. During the nestlings’  last days in the hole, they received an increasing number of bright red arils from the seeds of the “candela” a large tree of the nutmeg family that was then beginning to ripen its fruits.

Usually the big seed had been removed from the enclosing aril before the parents brought the latter to the nest. These brilliant arils could have come only from the forest 200 yards away, where the tityras seemed to find most of their food. They were never seen to forage in the cornfield in the midst of which their nest was situated. At first, the parent entered the hole and was completely hidden from me while it fed the nestlings, although sometimes I could detect its tail sticking up in the top of the cavity.

When the young were 12 days old, the parent fed them while clinging upside-down in the doorway, its foreparts down in the hole and the tip of its tail projecting from the top of the aperture. Sometimes after delivering the meal it entered to turn around and perhaps collect a dropping, and sometimes it backed out. After the nestlings were 18 days old, the parent nearly always clung to the trunk and passed the food through the doorway; very exceptionally, if the young were sluggish in taking the meal, the adult would enter to deliver it.

At first, the parent clung in front of the doorway, but later, when the nestlings stuck their heads out to receive their meals, it might cling around the side of the slender stub, somewhat above the level of the doorway, and reach down to place the food in the recipient’s open mouth. The parents took fairly equal shares in feeding the nestlings, but on most mornings the female fed them more often than did the male. In 30 hours of watching, she brought food 53 times, he 40 times.

At an inaccessible nest with at least two young that were no longer brooded by day, the male brought food nine times and the female ten times in three hours. If the male arrives with food while his partner is in the nest brooding recently hatched nestlings, he does not, like many male birds, give it to her to be passed to the little ones she covers, but he alights nearby and continues patiently to hold the morsel until, at her own good time, she departs, leaving the nestlings free to receive what he has brought for them.

I have seen this inefficient behavior at several nests. Once I watched a male wait for a quarter of an hour, from time to time going to look into the hole, or voicing a slight grunt to proclaim his presence, until at last his brooding partner flew away and he could feed his offspring. At times, however, the male tityra grows tired of waiting for his mate to leave and carries away what he has brought. At one nest, the male somehow lost his tail, but despite this handicap, he continued faithfully to feed the nestlings.

Sanitation - During five hours of the sixth morning after the nestlings hatched, I saw only one dropping carried from the nest, by the male. Additional droppings had evidently been swallowed by the parents inside the hole. On the twelfth morning, the white fecal sacs were carried away although sometimes they were swallowed. By the eighteenth morning, the parents could reach inside to take the droppings while they clung before the doorway; less often, they entered to remove a dropping.

On the the twenty-seventh morning, the male entered the nest after delivering a lauraceous fruit, evidently to clean the interior. When he tried to come out, he was stuck in the doorway. After a great struggle to squeeze through, he finally emerged upside down! Later the female also had a hard time getting out, yet both had entered without difficulty. Possibly while cleaning the nest they had swallowed enough of the large seeds regurgitated by the nestlings to increase their girth to an unusual degree.

This explanation was suggested by the recollectioln of a Blue-throated Toucanet which had entered a nest hole with a lauraceous fruit that seemed too large for his nestlings to swallow. When he tried to pass outward through the doorway by which he had entered, he stuck so firmly that he could not move until he reduced his girth by regurgitating the fruit, which he held in his bill until he regained his freedom, then swallowed once more. During the young tityras’  last few days in the nest, the parents often swallowed the droppings instead of carrying them away in their bills.

The young birds had remained beyond the time when their feces were enclosed in the gelatinous sacs that facilitate their disposal. He leaves to the in earlier years, I had often seen tityras carry pieces of leaf to nests that held young. Sometimes the parents dropped these bits of the leaf while they rested near the hole, and sometimes they did so while clinging in front of the doorway. At times the parents at this latest nest brought an odd billful of leaves, which they might drop or take into the hole, and at intervals, they brought this material in a concentrated, purposeful manner. Thus, between 10:00 and lo:19 on the sixth morning after the nestlings hatched, the male entered the nest five times and the female four times.

Sometimes they went in so swiftly that I could not see what they carried, but on four occasions I clearly saw that they held leaves, and I believe that on all of the nine visits they brought this material rather than food. In all the rest of the morning, up to 10:30, they fed the nestlings only ten times. The parents are especially likely to bring leaves and drop them outside the nest in moments of excitement, as when some critical event in the nesting cycle has just is about to occur, or when their nest has just been visited by a man. It will be recalled that the first two billfuls that the female brought to the nest after an egg hatched were leaves, not food.

And two minutes before the first nestling flew from the nest, the female came with leaf fragments, which she dropped in front of the young bird’s open mouth in the doorway. Another female tityra, whose three-week-old nestlings had apparently just been lost, gathered a billful of dead leaves in the top of a neighboring tree, then let them fall to earth. The drive to gather leaves is strong in tityras apparently because leaves play an exceptionally large part in the birds’  domestic economy.

Not only are they the principal-sometimes the only-ingredient of the nest, but for some five weeks they serve to conceal the eggs and young from predators that might look into the hole. And at an earlier stage, tityras often gain possession of the holes in which wood- peckers or araqari toucans sleep or are preparing to nest by filling them with leaves and other materials with such persistence that the occupants finally abandon them, as told in more detail beyond.

Development and behavior of the nestlings.-My single reasonably adequate view of a newly hatched tityra revealed that it was blind, with pink skin that bore a few tufts of light-colored down. In the next few days, the glimpses I had of small portions of the nestlings that showed through the leaves revealed that their skin had become much darker, but it never became quite black.

Once I heard a weak peep peep peep while I looked into the nest, and occasionally the leaves would move, but usually the nestlings lay in silent immobility. After a few days, I was more likely to see portions of their heads than of their bodies, and when they were ten days old, I found both nestlings lying with their heads completely free of the leaves which covered the rest of them. Three days later, they were also lying with exposed heads and concealed bodies. Then, when the elder was 15 days old, I discovered one of them resting wholly exposed, although only the head of the other nestling was visible. Thereafter, throughout their final two weeks in the nest, they were never again found beneath the leaves. They were always silent and immobile while I peered in at them.

When, after an the interval of two weeks, I, at last, saw the nestlings entire, their dark skin was still nearly naked. The pins of the remiges were prominent, but those of the rectrices were much shorter. I could no longer detect any natal down them; possibly much of it had been rubbed off by the leaves that covered them, but an odd tuft was still present when they left the nest. While I looked in, they kept their eyes tightly closed. They were silent; nothing that I could do, from the time they hatched until they left, would stimulate them to open their mouths. Two days later, when the nestlings were 17 days old, their eyes were open, and both the contour and the flight feathers were expanding at the tips of their sheaths.

At this age, the young could reach up so far that the parents fed them without entering the nest. Once, indeed, I glimpsed an open mouth in the doorway, and at last, learned that the interior was orange-yellow. The flanges at the corners were whitish. When the nestlings were three weeks old, they were at last fairly well covered with plumage, but their flight feathers were still largely unsheathed. Now, if they were very hungry, their heads would often appear in the doorway when a parent arrived with food. Aside from the weak peep’s that I heard from the nestlings when newly hatched and again a few days later, I heard no note from them until the fifteenth day after they hatched-the day on which I first saw one of them completely exposed.

While I stood only about 25 feet from the nest, hardly concealed by the maize plants, the male flew to the top of the stub with food in his bill. Recognizing the arrival of the parent by the sound or vibration he made when he alighted, the nestlings repeated little sharp notes while he stood hesitating. They continued this chorus while, standing in the doorway, he fed them. Two days later I approached carefully, tapped the trunk and shook it slightly, trying to reproduce the sound and vibration made by a parent alighting there.

The nestlings set up a chorus of the sharp notes that I had previously heard, but they fell silent as soon as I set the ladder against the stub. Soon they learned to distinguish my simulation of a parent’s arrival from the real thing, and would no longer respond to it. Until they left the nest, I heard their peculiar, sharp notes with increasing frequency, especially when they were hungry. I can best describe them as “sucking” notes, such as one can make by suddenly opening his lips as he draws in his breath.

Departure.-On July 13, when the nestlings were 24 days old, the female from time to time alighted on the top of the nest stub and called. On the next day, this behavior was more frequent and pronounced. Without food, she would come to stand on the end of the stub, a few feet above the nestlings, repeating her sharp, dry notes and twitching her tail with a rapid movement that combined a slight fanwise opening and closing with a little vertical flick. Her calls consisted of one, two, three or, rarely, four notes.

The monosyllable, a frequent call at all seasons, was the strongest. The more syllables that the phrase contained, the shorter and weaker each became; the insect-like notes of the tetrasyllable were so weak and rapidly delivered that it was difficult to distinguish all of them. These short, dry notes, uttered with twitching tail, suggested urgency and impatience. After standing atop the stub and behaving so for a few minutes, the female might fly off, only to return promptly and repeat the performance.

She was obviously trying to call out her nestlings, now well feathered. The male never behaved in this fashion. From first to last, he seemed not to care whether they stayed in the nest or left, but continued faithfully to attend them wherever they were. The female’s excited notes were not without effect on the nestlings. At eight o’clock, while she stood calling on top of the stub, a young tityra pushed its foreparts through the doorway, farther than I had seen it emerge before. Then the male gave it a large green insect, and it went down inside.

When the female repeated her performance half an hour later, a nestling stood on the door-sill, looking around and giving “sucking” notes that were audible to me 60 feet away. But soon it returned into the nest. Later in the morning, it again leaned so far out that I expected it to leave, but it did not. On the following day, July 1.5, the female seemed less eager to bring her family into the open. Although she rested a good deal atop the stub, she did not, as on the preceding day, arrive there without food. While standing there, she called much less, and her voice sounded less urgent. Likewise, she twitched her tail much less.

Apparently, the excitement caused by the nestlings’  greater activity and the imminence of their departure was on July 14 expressed by impatience, at least on the part of the female, to have them make their exit, whereas on July 15 it was expressed by a greatly accelerated rate of feeding by both sexes. On this morning the parents fed the nestlings twice as often as on any previous morning that I watched them.

On July 16, when the elder nestling was 27 days old, activities at the nest followed much the same pattern as on the preceding day, with occasional calling by the female from the top of the stub, responses by a nestling that brought it into the doorway but no farther, and an even higher rate of feeding. Tityras of two species (see the preceding life history) have been more obviously eager to have their young leave the nest than any other birds that I have watched, most of which have seemed indifferent whether their offspring lingered in the nest or came out into the world.

The fact that the tityras’  attempts to induce their young to leave were associated with a greatly accelerated rate of feeding weighs heavily against the persistent belief that parent birds withhold food from their young to force them by hunger to leave the nest. Such behavior might defeat its own purpose, for unless the nestlings promptly gave the desired response, the longer it was continued the more debilitated and the less able to meet the demands of life in the open they would become.

On July 17, when one of the nestlings was just four weeks old, I arrived later, at 6:35 a.m. while the sun was shining brightly. Neither parent appeared until 653, when the female came with a billful of leaf fragments, which fluttered to the ground when she dropped them in front of the open orange-yellow mouth of the nestling in the doorway. Then she rose to the top of the stub and called with single, double, and triple notes.

She flew off, but promptly returned and called as before. The young bird which had been standing in the doorway looking out now launched itself and flew down into the corn, with the female following from the top of the stub, at 6: 5 5 a.m.

As soon as the first fledgling left the doorway free, the other one looked out. The female returned to the top of the stub and called briefly. During the next two hours, she tried hard to induce it to leave, in the manner already described. Often it stood in the doorway as though about to go, but it was not yet ready. In these two hours, it was offered food seven times by both parents, but once it refused because it was satiated. I could not see how many meals the fledgling down among the maize plants was receiving.

At nine o’clock, I went to look for the fledgling, which I promptly found on the ground in front of the nest. It tried to escape me by hopping over the ground and flitting from one charred branch or prostrate log to another, but despite these obstacles to my progress, I soon caught it. When I picked it up, it hardly resisted. The fledgling was well feathered, its plumage resembling that of the adult female. Its dusky remiges were well developed, unsheathed only at the base for a quarter of their length or less. Its blackish tail feathers were rather long but still about one-half unsheathed.

A single tuft of natal down, long, loose, and light gray in color, adhered to the tip of a contour feather on the back but became detached and blew away. The fledgling’s bill was blackish, slightly lighter at the base. The whole interior of its mouth was bright orange-yellow, and there were whitish flanges at the corners. Its eyes were deep brown, and the bare skin surrounding them was grayish, instead of red as in the adults of both sexes. Its legs and toes were plumbeous.

I set the fledgling on a stump near the nest, where it stayed. It seemed rather underdeveloped to have left its sheltering nest. Next morning, I found it 50 yards away, beneath a dead tree standing in the middle of the milpa, from which the parents had been dropping almost straight down with food in their bills. The fledgling was perching as high as my head on a dead branch. Far more alert than the day before, it took wing as I approached and flew off competently to alight on a maize plant.

It now seemed quite able to escape all but winged pursuers. For two days after the departure of the first fledgling, the parents continued to feed the other young tityra in the nest. In this interval, the female tried again and again to persuade it to leave. Although her excited urging obviously stimulated it, it would look from the doorway, rapidly repeating cucking” notes, only to lose courage and back down into the safety of the hole. It did this again and again.

Once, indeed, while taking its meal, the nestling stretched out so far that one leg slipped outside. After a struggle, it pulled itself back into the cavity. Finally, at 8:OS a.m. on July 19, the adult female alighted atop the stub and called, as she had done so many times before. The nestling alternately looked out and withdrew. But when, a minute later, its parent flew off, calling, it flew from the doorway in the same direction, to come down among the corn. Three minutes after this, the female returned with a large insect, which she took to the doorway of the empty nest.

After looking in several times, she carried it down to the newly emerged fledgling. Both of the young tityras left the nest while their parent was calling for them to go, but apparently her urging was effective only after their own internal development had prepared them to respond to it. For tityras, it may be more important to leave the nest only in the presence of a parent than it is for most other land birds. Many of their nests are so situated that they must fly hundreds of feet before coming to rest, and they might be lost if no parent watched or accompanied them.

Moreover, on this long flight the fledgling would be particularly vulnerable to a bird of prey, and their parents doubtless would not call them out if such an enemy were in sight. Leaving my observation post, I found the second fledgling in a patch of bracken fern only three yards from the nest stub. When picked up, it bit my finger gently and struggled a little, but soon rested quietly in my hand. Its plumage was slightly less developed than that of its nestmate had been two days earlier.

When I set it on a fallen branch amid the maize, the female alighted four yards from me and only about a foot above the ground-closer to me and to the earth than I had ever seen an adult tityra before. She called the fledgling with phrases of two and three syllables, as she had done while coaxing it to leave the nest. It hopped over the ground and fluttered toward her; it could fly only a few feet. Calling as before, she flew toward the dead tree in the center of the milpa and the fledgling fluttered after her. This was the last time that I saw either fledgling. Next day I could find neither them nor their parents in the cornfield.

Doubtless, as is usually the way when a brood is raised in a clearing, as soon as the young birds could make the journey they were led to the neighboring high forest, whence I heard a tityra’s call. The first nestling had remained in the nest a full 28 days, the second, 29 or possibly 30 days. Probably they survived this long period in their low nest because I had wrapped an opened five-gallon tin around the stub to keep down climbing animals. A slight push sufficed to overturn the rotten stub so that I could examine the contents of the nest. The doorway was 2 inches in diameter. The soft wood at the lower edge of the orifice had been worn down by the tityras’  feet during the two months that they had been passing through and clinging to it. The cavity, which ex- tended 9 inches below this edge, was 3 to 3% inches in diameter.

On the bottom was a little dry moss. I do not know whether the tityras had carried this in; I have never seen them with such material. Above the moss was an accumulation, 2 or 3 inches thick, of pieces of brown dead leaves. The lower part of this litter was compacted into a coherent mass, but the upper part was loose. The largest piece was a nearly whole leaf 2% inches long by half as broad, but most of the leaf fragments were much smaller, ranging down to tiny bits. Mixed with the loose leaves were many regurgitated seeds, chiefly of the lauraceous fruit that I had so often seen the parents carry in, detached fragments of the legs and wings and other parts of large insects, and three small snail shells.

There were also a few whole shriveled fruits of the same lauraceous tree. The nest had been kept as clean as could be expected, given the tendency of waste to slip down among the loose leaves where it was difficult for the parents to find. Although the hole had a peculiar odor, I detected no vermin of any kind. For 18 days after two young tityras left a high nest in a clearing, I could not find them. Doubtless they were being attended by their parents in the neighboring forest.

At the end of this interval, they sometimes followed the adults into the clearing, where the female was incubating a second brood. After a few more days, they were no longer seen in the vicinity, having apparently become self-supporting about three weeks after quitting the nest, at the age of about seven weeks. THE SECOND BROOD In Costa Rica, the tityras frequently, if not regularly, attempt to rear a second brood when they have successfully brought forth their first brood at an early date.

A female whose nestlings had departed on or shortly before April 29, 1936, was seen to enter and rest in the doorway of the nest hole on May 9 while she and her mate were still feeding two full-grown young birds. On May 11, she went into the cavity in the evening to pass the night. By May 17, she was certainly incubating again in the nest where her first brood had been reared, leaving her mate to attend the young birds, which seemed rapidly to be becoming self-supporting. By June 5, both parents were feeding the nestlings of the second brood, their older offspring having meanwhile gone their own way.

By June 25 the nest was empty; and although the fledglings could not be found, the aggressive behavior of the usually mild parents suggested that their young were hiding nearby. In later years, additional evidence for second broods was gathered. Nestlings have been found as late as mid-July. TERRITORIAL RELATIONS The Masked Tityra is decidedly a ‘Yerritorial” bird.

Indeed, it is one of the relatively few tropical birds, especially among those of the treetops, which I have seen engage in disputes over territory, although these have been carried on with less violence than is often witnessed in similar contests by northern birds. A clearing by the forest, several acres in area, may contain a number of fire-killed trees, each of which has one or more holes that would be suitable nest sites for tityras; yet I have never known more than one pair to breed in such a clearing.

The only tityras’  nests that I have seen at all close together were those in the three palm trees already mentioned. Possibly the circumstance that the wide-spreading fronds of the palms screened the tityras from each other, enabled these three pairs to nest closer together than one would find them in the usual dead and naked trunks, where they are visible from afar. While one pair of tityras nested in a tall dead trunk in a clearing beside the forest, a second pair came to investigate the woodpeckers’  holes in another dead tree about a hundred yards distant. Presently the visiting female brought a piece of dead leaf, but as she carried it toward the hole that she had chosen, the resident pair discovered the intruders and, flying at them, drove them unresistingly away.

Two days later, in a neighboring clearing, I watched a female, evidently the one which had been denied the use of a cavity, try again and again to force herself into woodpeckers’  holes too small for her, while her mate looked on. This behavior suggested that there was a shortage of suitably isolated holes for the tityras. At the end of February, when a pair of tityras established in a large clearing were preparing to nest, their territory was invaded by a small flock of their kind, consisting of four males and a female. The invaders and the resident pair rested not far apart, called in their thick, grunty voices, and twitched fanwise their short, black-and-white tails.

Presently one would dart at another, who would quickly change his position to avoid a collision; and this might cause a general shifting around of the whole group. After a while, one would start to fly across the clearing, and some or all of the others would follow closely. They might all settle together in another tree in the clearing or at its edge, or else they would fly beyond sight over the neighboring forest. But soon they returned to grunt, dart at each other, and fly about in a loose flock as before.

In the ensuing days, the number of invaders dwindled, until the resident female was followed by only two males. When finally the number of males had been reduced to one, her mate, the female gathered a billful of leaves and took them into the hole-the first material that she carried inside in my presence. Weeks later, when the resident pair was feeding nestlings in this hole, two trespassing males followed the female as she took food to the nest. They perched nearby until the male parent of the nestlings arrived with food and, without even clearing his bill, drove them away simply by darting toward them.

Unattached male tityras seem often to travel two or three together in search of a mate, and their presence at the height of the breeding season indicates that there are more males than females. From May 24 to June 17 of 1939, two pairs of tityras contended for the possession of a tall, many-branched, dead tree that rose above a low second-growth thicket 200 yards from the forest, and which apparently they desired for rearing a second brood. This arboreal skeleton contained enough unoccupied holes to provide nest sites for several pairs of tityras, but each pair insisted on having exclusive possession of the tree and the surrounding area. The protracted dispute was carried on with characteristic mildness of temper, patience, and persistence. All four of the tityras would rest among the dead branches, often close together, apparently in perfect amity.

Of a sudden, one would dart at a member of the other pair, causing it hastily to shift to a different perch. Then all would flit about confusedly for a few moments, apparently greatly excited, voicing their grunty notes and twitching their tails as they rested between movements. They rarely, if ever, struck each other, for the individual which saw itself the object of another’s attack invariably retreated. When the flare-up ended without any participant having suffered the slightest injury, all rested from their nervous exertions quietly side by side as before.

Soon becoming hungry, all four flew off to the forest, where doubtless they foraged in unruffled fellowship. After a brief absence, all four returned together to the dead tree, to resume the interrupted argument in the same intermittent fashion. Some times the dispute continued until evening, when the two pairs flew toward the woodland as though to roost together. By June 25, a month after I found these two pairs quarreling oven the tall dead tree, neither pair had begun to nest in it.

The season was now so far advanced that further breeding was improbable. Were tityras fiercer and more decisive birds, doubtless the dispute would have been settled promptly, possibly by the maiming or death of one or more of the contestants, and the victorious pair would have proceeded to nest. But the two offspring which they might then have reared, if enemies of many kinds had not destroyed the eggs or young, would merely have sufficed to replace the casualties of their battle; the net increase of the local population would have been small or null.

Since in this locality tityras were already so numerous that every clearing which provided a nest site had a breeding pair and there was a shortage of suitably isolated old woodpeckers’  holes and other cavities, the failure of these two pairs to rear broods (probably second broods) was far from deplorable; for any increase in the population would have created more serious difficulties in the following years. We often wonder how tropical birds preserve their numbers at a fairly constant level from year to year, avoiding the great fluctuations in population which many birds and mammals of high latitudes exhibit.

This episode of the tityras shows us one of the ways in which the regulation of numbers is accomplished. While the Masked Tityras argued over the dead tree, a pair of Black-crowned Tityras built their nest in one of its cavities, undisturbed by them. Although rather similar in coloration, Black-crowned Tityras do not arouse the territorial jealousy of the Masked Tityras, as do others of their own species. The former may rest undisturbed close by a nest of the latter, and both at times breed in the same clearing. Although tityras defend nesting territory, they seem not to defend a feeding territory. Since the clearing where they often nest provides little or no food, it is strange that a breeding pair claims such a large area.

RELATIONS WITH OTHER BIRDS

As in many other birds which nest in holes which they do  not make, the tityras’  mode of life brings them into competition not only with wood-carving species but also with other hole-users in the same plight as themselves. In the first category are the woodpeckers whose holes they covet, often before the makers have abandoned them; in the second class are Southern House Wrens, Gray-breasted Martins, Black-crowned Tityras, and, above all, aracari toucans, which nest and sleep in holes carved by the larger woodpeckers. In El General, a favorite nest site of the tityra is a deep, spacious cavity carved high in a fairly sound dead trunk by Golden-naped Woodpeckers. One great advantage of these holes is that the narrowness of the doorway keeps out Fiery- billed Aracaris, which easily enter chambers made by larger woodpeckers such as the Lineated and the Pale-billed.

After a successful nesting, a pair of Golden-naped Woodpeckers sleep with their offspring, often in the hole in which the latter was reared, until the the approach of the following nesting season, when the young disperse and the parents move into a newly carved hole in which the female soon lays. Tityras may carry litter into the woodpeckers’  old dormitory before the new one is large enough for occupancy.

When the woodpeckers arrive in the evening and find the bottom of their usually clean chamber covered with trash, they may throw out many pieces, but at other times they sleep above it. If another old hole is available, the Golden-napes may roost in it rather than in that which the tityra is filling. In these circumstances they are often very unsettled, changing their lodgings a number of times until they are finally installed in the new hole, where they soon incubate. I have seen a pair of tityras dispossess, without any fighting, a pair of Golden- napes of the lodging they had occupied for many months.

If the woodpeckers were carving at their new hole lower in the trunk when the tityras arrived, they appeared uneasy and sometimes flew away. Rarely a tityra darted toward a woodpecker while it was at work and caused its prompt retreat. But the tityras also seemed to be slightly afraid of the woodpeckers, so that encounters were carefully avoided by both parties. Similar relations between Golden-naped Woodpeckers and Black- crowned Tityras are described in the chapter on the latter.

Although tityras are usually mild, peaceable birds, occasionally one finds an individual with a fiery temper. While a pair of tityras and a pair of Golden-naped Woodpeckers reared their early broods in the same dead tree, I noticed no enmity between them. But while the female tityra was preparing to rear a second brood in the same hole as the first, her attitude toward her picarian neighbors changed. One evening she perched at the top of the tall dead tree and darted at the woodpeckers as they approached their hole, which had now become the dormitory of the parents and two male offspring. Swooping down, with an audible snap she came so close that they fled to other trees, and she repeated this threat whenever one of them returned.

She kept the woodpeckers out until long past their usual hour for retiring, but as it was growing dark she stood quietly atop the trunk and watched them cautiously slip into their chamber below her. Next morning, she twice flew menacingly at a Golden-nape which rested inoffensively in a treetop 50 yards from her nest. But after this she calmed down and incubated her eggs without, as far as I saw, again molesting her near neighbors the woodpeckers. On the Caribbean slope of Costa Rica, I watched a pair of tityras gain possession of a freshly carved hole in which Black-cheeked Woodpeckers seemed to be preparing to nest. When the female tityra carried leaves into their hole, the woodpeckers promptly began a new cavity lower in the same trunk, where, as soon as it was large enough, they slept and later nested.

Here, as with the Golden-naped Woodpeckers, the change in possession of the hole was effected, as far as I could tell, without any fighting. I have not known tityras to try to capture a woodpecker’s hole that held eggs or nestlings. High in the mountains, a male Golden-olive Woodpecker proceeded to throw out the material which a tityra had carried into an old cavity, in which he had not recently been sleeping and which, apparently, he did not desire for nesting. Although the woodpecker continued on two days to clean out this chamber, I noticed no fighting between the two kinds of birds.

When the woodpecker looked into the hole and found a tityra within, he promptly flew away as though alarmed. The tityra’s relations with the brilliant Fiery-billed Aragaris are more complex than those with woodpeckers. Not only do the two species compete for the possession of the big holes abandoned by the early-nesting Pale-billed and Lineated woodpeckers, but the tityras fear these great-billed nest-robbers for the injury they may inflict on themselves or their offspring. Sometimes the tityras choose as a nest site a cavity in which several araqaris roost.

At first, perhaps, they are unaware that the hole has prior claimants, for the toucans may be absent in the daytime while the female tityra carries leaves into their dormitory. Soon, however, the tityras discover that they have to contend with these birds to which all the smaller feathered creatures have a great antipathy. Then, as the day ends, the tityras take com- manding positions near the hole, from which they harass the aracaris when they come to enter their dormitory, darting back and forth above their heads while they perch, pursuing them closely in flight, and swooping close by them while they cling before the doorway to inspect the interior of their cavity before they enter.