Thursday, 7 September 2023

Naming and identifying birds


This article presents descriptions of the habits, behavior, appearance, and distribution of every species of bird that breeds in or regularly visits Australia.

Species names

Every species of animal and plant is given a formal and unique scientific name by which it can be known; no two species can have the same name under the International Code of Zoological Nomenclature. In birds, a species is a group or population of similar-looking and similar-behaving individuals that interbreed in the wild and produce fertile offspring.

The scientific name of a species derived from Greek or Latin has two parts, a second part or specific epithet that identifies the species itself and a first part or generic name that identifies the genus, the group of species to which it belongs. Closely related species are grouped in genera so that their relationships may be understood at a glance. Thus the Long-Tailed Finch, identified by its epithet acuticauda, is closely allied to other species of grass finches in the genus Poephila: hence its full scientific name, Poephila acuticauda.

The generic name always begins with a capital letter and the species epithet always with a small one. The scientific name is, by convention, always printed in italics except where it occurs in italic context. In some cases, a triple name is used. The third name indicates the subspecies, or race, a level of classification for birds of the same species that look different and live in different regions. Unlike other zoological and botanical fields, in ornithology, every bird also has a recognized English or common name.

Birds may be known by many common names and at times popular names are superseded by others more widely used internationally. The most frequent of these alternative names are listed under 'Other Names'. Birds and animals are also grouped into many other hierarchies of classification above the levels of species and genus. The Australian Magpie, for instance, is grouped with currawongs and butcherbirds in the family Cracticidae. This family is, in turn, grouped with approximately 33 other families occurring naturally in Australia in the order Passeriformes, the perching birds, or songbirds. This and 26 other orders are grouped in the class Aves, which comprises all birds. A description of the orders and families of birds found in Australia is given.

Ornithologists are constantly reclassifying birds in the light of new studies, necessitating frequent changes in scientific names and their order. Most changes flow from generic readjustments to the position of species, and from the discovery that distinctive populations previously regarded as separate species hybridize and intergrade and so are one.

After each bird's name, the describer is credited, together with the year of the first description. This shows that most Australian birds were named over 100 years ago. Brackets around a describer's name indicate that the genus in which the species is now placed is different from the one in which it was first described.

Source of classification

The classification of species and genera follows the forthcoming edition of the Royal Australasian Ornithologist's Union's (RAOU) checklist of the Birds of Australia and Territories, published in the Zoological Catalogue of Australia series by the Bureau of Flora and Fauna (BFF), Canberra. There are some minor departures from the catalog in the sequence of species, genera, and families, but the taxonomic adjustments already reached by the compilers are incorporated here.

Authority for names

Scientific and English names used here also follow those of the RAOU-BFF catalog. By convention and consensus, that list sets the standard for Australian nomenclature and has done so for the past 50 years. The recommendations of the RAOU's committee of experts-B. Glover, F. Kinsky, S. Marchant, A.R. McGill, S.A. Parker and R. Schodde have been adopted in the forthcoming catalog, and here, except in a few cases affected by the classificatory change. To perpetuate popular but parochial names where they conflict serves little purpose other than to destabilize nomenclature, stir controversy, and certainly bewilder the amateur bird-watcher.


The length or height of each bird is given. Measured from the tip of the bill to the tip of the tail, it is rounded off to the nearest five millimeters. Where the bill or the tail is unusually long, its form is stressed.


The bird's color pattern is described as working usually down the back and then down the front to the belly and undertail region, ending with the colors of the iris of the eye, the bill, and the feet. The technical terms for parts of a bird's body are explained on the facing page. Different authorities sometimes use different names for the same color, especially subtle greys and browns, but the accompanying photographs provide guidance.

Some birds, especially males, have two or more different plumages during the year. Dull plumage is often replaced by bright at the beginning of the breeding season, and both plumages are described. Young birds are called chicks or nestlings until they can fly. When young leave the nest, they are said to fledge. Free-ranging chicks that are likely to be seen, such as ducklings, are described as downy young.

Those of Northern Hemisphere breeding waders. however, are excluded because they are never seen in Australia. So are the chicks of most songbirds, because they are so naked. The next stage a young bird passes through is its first plumage of true feathers. It is then called immature. This stage may last for several years in some species, such as the Satin Bowerbird, and the birds may pass through several plumage phases. Where there is a distinct immature plumage, it is described briefly.


The sounds birds make can be important guides to identification. They call to warn of danger, to keep in contact with one another, to keep a flock together while feeding. These calls may be described as zit-zit-zit, for instance, others are so elusive that they can only be described in general terms such as 'harsh chattering sounds'. During the breeding season, and even throughout the year, birds utter phrases to proclaim their territory and attract a mate. Those phrases are often pleasant to hear and, in the case of songbirds or passerines, are called songs. Wherever possible, each bird's different calls and songs are described separately in the passerines.


Many birds have distinct breeding seasons, in the spring in the south, for example. In the north other birds-seed-eating parrots and finches-have their breeding geared to the end of the wet season, when food is plentiful. Still others, in arid regions, may breed at any time after good rains have fallen. Most birds build a nest, fairly typical for that species, in a fairly consistent place and height. The form and structure of each nest are described.

Eggs are also described by number, size, approximate shape, and color. Eggs laid in concealed places are often white, whereas those laid in the open are often colored and marked in a way that blends with their substrate. The large end, which emerges first, is often more heavily marked. The size of eggs varies; the average is usually given for each species, to the nearest millimeter. The common clutch size is also given.

This is usually the same within a range for each species, but where food is unusually abundant the clutch may be exceptionally large; and in times of scarcity eggs may not be laid at all. Incubation and fledgling periods are given wherever possible, the latter recording the period to flight, not the day of quitting the nest by precocial chicks. If they are lacking, they have not been found.


Each species has its own range, determined by the availability of suitable habitat and food. This is described in detail just for Australia. Within their ranges, some birds are sedentary-they stay in one locality throughout the year while others migrate between two places, and yet others wander nomadically. Because Australia is so vast and sparsely populated, knowledge of bird distribution has been sketchy.

To rectify this, the Royal Australasian Ornithologists Union has just finished a five-year project studying the distribution of birds throughout Australia and has produced an atlas of their ranges. The maps show the ranges of most of the species and are based on the RAOU Atlas. These maps are necessarily simplifications of complex patterns and few if any birds will be seen at all places throughout their ranges. Places where species occur as rare vagrants are not shown on the map but are mentioned in the accompanying text. Maps have not been included for some birds that visit Australia only occasionally.

These are mostly seabirds, which can be blown ashore anywhere along the coast. For seabirds, only the coastal distribution is mapped. Many of them, of course, range far beyond the coast. The overseas range of these birds, and of others occurring beyond Australia, is summarized in the text. The maps include the Tropic of Capri- · corn, state boundaries and, as reference points, the sites of Adelaide, Perth, Broome, Darwin, Alice Springs, Cairns, Brisbane, Sydney, Melbourne and Hobart. At the end of the distribution notes, the approximate number of races is given, stressing those found in Australia.

What to look for

For most people, an interest in birds begins with identification the pleasure to be had from putting the right name to a bird. But success in identifying birds depends on knowing how to look at them. This is not simply a matter of being alert but is a technique that can easily be learned. The most important clues to a bird's identity point to which special attention should be paid: size; shape, including the shape and length of the bill; general coloring of the plumage and noticeable markings; behavior; call and song; when and where the bird was seen. Because some birds visit Australia at only a certain time of the year, when a bird is seen may be a clue to its identity.

The flight pattern is another. Is it direct or meandering? Powerful or fluttering? Does the bird fly in short bursts or is flight sustained? Then there is the method of flight. A bird may use its wings almost all the time in flapping flight or it may glide on outstretched wings; it may hover in one place or it may soar. Or its flight may be undulating a fairly regular pattern of alternate flapping and gliding.

Further points to watch for are the way a bird walks, runs, or hops and where and how it feeds- by diving or hawking, or by probing bark or gleaning foliage. Shapes of Eggs Birds' eggs vary greatly in their shapes. Some basic shapes are shown here, but there are many intergradations. Birds of the same species usually lay eggs of the same shape.

Monday, 1 May 2023

American Goldfinch Call and Song

The American Goldfinch is one of the most beloved birds in the United States. It is known for its bright yellow coat and its distinct call and song. As summer approaches, its cheery call is often heard in the early morning, as the male American Goldfinch begins to sing to attract a mate. The American Goldfinch call consists of a few short, sharp notes that rise in pitch and volume, before ending on a slightly lower pitch than the beginning. It has been described as a “per-chic-o-ree” sound. The song is a cheerful, warbling tune that usually consists of several stanzas, each with several phrases.

American Goldfinches are social birds and often travel in groups, often found in flocks of up to several hundred. In these flocks, the males will often sing in unison to attract more females. While the males sing, the females usually remain quiet, listening carefully and choosing the one they find most attractive. The American Goldfinch has a wide range and can be found in most of the United States and Canada. During the winter months, they migrate south to places like Mexico, Central America, and the Caribbean. During the summer months, they head back north and can be spotted in many parks and gardens. The American Goldfinch is an amazing bird and its call and song are beautiful. If you’re out and about in the early morning, keep an eye out for these cheerful birds and enjoy the sound of their cheerful tunes!

Tuesday, 28 February 2023


Maintaining awareness of the latest market news, consumer concerns, and cutting-edge technologies will stimulate sales and build a loyal client base. The idea One of the most effective ways to keep your company current and cutting-edge is to cultivate an awareness of changing consumer concerns. Understanding your customer is vital to good business, but clients are not fixed on their desires. 

Their needs and wants change regularly, and for a variety of reasons—to claim you are truly at the forefront of your industry you must maintain knowledge of, and cater to, these changing demands. Subaru’s 2006 marketing strategy is an impressive example of this—every buyer of selected new Impreza, Forester, and Legacy models received £3,000 worth of free fuel vouchers. Customers who purchased any other model in the Subaru range received £1,000 worth of vouchers. 

This deal, not offered by any of its competitors, connects with the widespread global concern about rising fuel prices. Instead of offering a traditional reduction in price to stimulate sales, Subaru understood the changing needs and concerns of its clients and used this to create a truly enticing price incentive. By blending innovation with a willingness to react to the latest market developments, it is possible for businesses to prosper in volatile environments. Talk to your current and potential customers. What do they value? What are their concerns? What do they want?

• Find out what businesses in other industries are doing to attract customers.

• Ask people at all levels of your business, including the “extended family” such as retailers or distributors, how they would keep the product appealing.

• Plan a series of product enhancements and sales initiatives. A constant series of incentives to buy is better than a desperate splurge (or a complacent lack of activity).

• Be prepared to test a range of ideas and initiatives. Find out what works best, where, and why, and see whether it can be replicated elsewhere.

Monday, 13 February 2023

The Roman Ship, "De Meern" is a well-preserved ancient ship

The Roman Ship, "De Meern" is a well-preserved ancient ship that was discovered in the Netherlands. It was discovered in the 1990s during the construction of a housing development near the town of De Meern. The ship is believed to have been built in the 1st or 2nd century AD and was used for transportation and trade. It is considered to be one of the best-preserved ancient ships in the world and provides valuable insight into the maritime culture and technology of the Roman period. The ship is now on display at the Rijksmuseum van Oudheden in Leiden, Netherlands.

Tuesday, 7 February 2023

Western Bowerbird (Chlamydera guttata)

The Western Bowerbird replaces the Spotted Bowerbird in the desert hills and ranges of central and Western Australia. Bower-building and behavior are similar, although the Western builds its avenue of sticks on a higher platform 150-200 mm above ground level.

There is so much resemblance between them that they have been considered races of the same species. Westerns, however, are much smaller and more colorful than their eastern counterparts. There is a difference in shape between the tail and the bill of this bird. Unlike the Spotted, its crown is scalloped, not streaked, and its mantle patch lacks the plain appearance that is characteristic of the species.

There is no evidence that they intergrade where they almost meet in the northern Simpson Desert. In their range, Western Bowerbirds prefer breaks where there is water for drinking and copses of leafy trees for shelter and food. As the female approaches his bower to inspect, the male calls out, fans his tail, jumps and flicks his wings, and performs ritualized dances. The pink crest on the neck will also be erected, as wall decorations held in the bill and shaken vigorously.
However, they are primarily fruit-eaters, eating drupes of sandalwoods and mistletoe within the crowns of shrubs and trees. Fig trees, Ficus platypoda, are found in pockets in many areas where the bird lives. Guttated Bowerbird is another name for it. Western Bowerbirds are about 250-270 mm long, but females are a bit larger.
Male: This male possesses a broad nape bar of dense lilac plumes over a dusky, closely scalloped ochre crown. There is a fleck of ochre on the tips of all feathers on the mantle as well as the rest of the upper parts, wings, and short tail. In the face and throat, the color is dusky, spotted with ochre. On the flanks and undertail, the color is yellow-cream, slightly barred, and variably washed with russet.
The eyes are brown in color. There is a black bill and a yellow mouth. Olive-grey is the color of the feet. The female has a scalloped crown, a shorter nape bar, a more heavily spotted throat, and a longer tail than the male. MALE: As female; nape bar absent. This bird has a similar call to the Spotted Bowerbird. Francis Gregory collected the species in 1861, and John Gould gave the specimen to him. As a result of its plumage, guttata is named spotted. There is a close similarity between this species and Chlamydera maculata, the spotted bowerbird.
The western bowerbird is polygamous, with males mating with several females over the breeding season and females taking care of nesting, incubation, and chick rearing. September-December is the nesting and breeding season. In trees, nests are made from loose saucers of dry twigs, lined with finer twigs and needles, and placed in horizontal forks. Usually two eggs; pale grey-green, covered with brown scrolls and occasional darker blotches; oval, 32 x 26mm.
From Birksgate, Warburton, Macdonnell, and Jervois Ranges to the edge of Gibson Desert, and south to CueLeonora, WA, the Western Bowerbird is found in central Australian ranges. In addition to the nominated Chlamydera guttatag, and C. guttata cateri, which occurs only in the North West Cape in Western Australia. Rock figs, sandalwood, snake gourd, and mistletoe are among the fruits fed to the western bowerbird. In addition to feeding on cultivated fruits, they will also enter farms to do so. Other items in the diet include nectar, flowers, beetles, grasshoppers, ants, moths, and moth larvae. It is rare to find them far from water as they need to drink regularly.

Sunday, 5 February 2023

What is graffiti art definition

Graffiti is a form of visual art that consists of writing or drawings made on public surfaces, typically without permission. It can range from simple text to complex murals and often involves spray paint or markers. Graffiti has a long history, with examples dating back to ancient civilizations, and can be seen as both vandalism and as a form of self-expression and social commentary.

Graffiti art is a form of visual expression that often uses public spaces as a canvas. It is created using a variety of techniques, including spray paint, markers, and stencils, and can take many forms, from simple tags to more elaborate murals. Despite its historical roots and cultural significance, graffiti art remains controversial, with some seeing it as vandalism and others as a legitimate form of artistic expression. Despite this, many cities around the world have embraced graffiti art and created designated spaces for it to be legally practiced.

Saturday, 4 February 2023

bullock's oriole vs hooded oriole

 Bullock's Oriole and Hooded Oriole are both species of birds in the family Icteridae. They are found in North America and belong to the same genus (Icterus).

Bullock's Oriole is a large oriole found in western North America, with a range extending from southwestern Canada to Mexico. They have a striking appearance, with a bright yellow head and chest, a black back and tail, and white wing bars.

Hooded Oriole is a smaller oriole, found in the southwestern United States and Mexico. They have a distinctive orange head and chest, a black back and tail, and a white patch on the wings.

Both species feed on nectar, fruit, and insects and are known for their beautiful songs. However, they are easily distinguished by their distinctive plumage, with Bullock's Oriole having a yellow head and Hooded Oriole having an orange head.

Friday, 7 October 2022

Barred Owl Call / Sounds

The barred owl is a powerful vocalist, with an array of calls that are considered "fantastic, loud, and emphatic". Calls probably carry well over 0.8 km. Its usual call is a series of eight accented hoots or the "typical two-phrase hoot" with a downward pitch at the end. 

Due to its best-known call, the barred owl is sometimes colloquially referred to as Old Eight-Hooter. Another call type is the "mumble", a grumbling, slurred, and subtle an up-and-down "twitter" calls at a high pitch. When agitated, this species will make a buzzy, rasping hiss about three times in three seconds, repeating every 10–30 seconds, and will click its beak together forcefully. 

The voice of the two sexes is similar, but the female has a higher-pitched voice with longer terminal notes. While calls are most common at night, the birds do call during the day as well, especially when provoked by human playback or imitation. They are more responsive than any hawk in the east to playback of calls of their own species. 

The barred owl is noisy in most seasons but peak vocalization times for barred owls tend to be between late January and early April. Two seasonal peaks in vocalizations, one right before breeding and another after the young have dispersed, with peak vocalizations on nights with extensive cloud cover. Peak times for vocalizations are between 6:00 pm and 6:00 am, with the least frequent vocalizations around mid-afternoon.

The barred owl also known as the northern barred owl, striped owl or, more informally, hoot owl, is a North American large species of owl. A member of the true owl family, Strigidae. Barred owls are largely native to eastern North America, but have expanded their range to the west coast of North America where they are considered invasive. Their diet consists mainly of small mammals, but this species is an opportunistic predator and is known to prey upon other small vertebrates such as birds, reptiles, and amphibians, as well as a variety of invertebrates. Barred owls are brown to gray overall, with dark striping on the underside. 

Barred owls have typical nesting habits for a true owl, tending to raise a relatively small brood often in a tree hollow or snag (but sometimes also in other nesting sites) in forested areas. As a result of the barred owl's westward expansion, the species has begun to encroach on the range of the related and threatened spotted owl. Evidence shows the assorted threats posed by the invading barred species are only increasing. In response, biologists have recommended culling operations to mitigate the negative effect of the barred on the spotted owl species. 

Thursday, 1 September 2022

House Wren

The house wren (Troglodytes aedon) is a very small bird of the wren family, Troglodytidae. It occurs from Canada to southernmost South America and is thus the most widely distributed native bird in the Americas. It occurs in most suburban areas in its range and it is the single most common wren. 

Adults are 11 to 15 cm long including wingspan and weigh about 10 to 12 g. The subspecies vary greatly, with upper parts ranging from dull greyish-brown to rich rufescent-brown, and the underparts ranging from brown, over buff, and pale grey, to pure white. 

All subspecies have blackish barring to the wings and tail, and some also to the flanks. All subspecies show a faint eye-ring and eyebrow and have a long, thin bill with a blackish upper mandible, and a black-tipped yellowish or pale grey lower mandible. The legs are pinkish or grey. The short tail is typically held cocked.

This bird's rich bubbly song is commonly heard during the nesting season but rarely afterward. There is marked geographical variation in the song, though somewhat more gradual than in the bird's outward appearance that can strikingly differ, e.g., on neighboring islands in the Caribbean. Birds from far north and south of the species' range nonetheless have songs that differ markedly. In North America, the house wren is thought to achieve the highest density in floodplain forests in the western Great Plains where it uses woodpecker holes as nesting sites.

In South and Central America, it can be found in virtually any habitat and is, as indicated by its common name, often associated with humans. North American birds migrate to the southern United States and Mexico for winter. Most return to the breeding grounds in late April to May and leave for winter quarters again around September to early October. These birds forage actively in vegetation. They mainly eat insects such as butterfly larvae, beetles, and bugs, also spiders and snails. Southern house wrens rarely attend mixed-species feeding flocks. 

The nest is made from small dry sticks and is usually lined with a variety of different materials. These include feather, hair, wool, spider cocoons, strips of bark, rootlets, moss, and trash. Nest cavities are usually a few meters above ground at most, but occasionally on cliffs as high up as 49 ft and more at least in southern populations. House wrens are feisty and pugnacious animals considering their tiny size. They are known to occasionally destroy the eggs of other birds nesting in their territory by puncturing the eggshell. 

Females thatsang more songs to conspecifics that were simulated by playback lost fewer eggs to ovicide by other wrens. Female bird song in this species is, therefore, thought to have a function in competition and is not only displayed by males. They are also known to fill up other birds' nests within their territory with sticks to make them unusable. 

Depending on the exact population, the house wrens' clutch is usually between two and eight red-blotched cream-white eggs, weighing about 1.4 g each and measuring 17 and 13.4 mm at the widest points. Only the female incubates these, for around 13–19 days, and she will every now and then leave the nest for various reasons. While she is on the nest, the male provisions her with food. The young, who like all passerines hatch almost naked and helpless, take another 15–19 days. 

 or so to fledge. 

Saturday, 20 August 2022

western meadowlark (Sturnella neglecta)

Approximately 8.5 inches (22 cm) long, the western meadowlark (Sturnella neglecta) is part of the icterid family. North America's western and central grasslands are suitable for its nesting. Bugs are the main food source, but seeds and berries also play a role. In contrast to the closely related eastern meadowlark, the western meadowlark has distinctive calls that are described as watery or flute-like. Besides Montana, Kansas, Nebraska, North Dakota, Oregon, and Wyoming, the western meadowlark is the state bird of six other states.

Wednesday, 3 August 2022

Facts of Mourning Dove

The Mourning Dove is the most widespread and abundant game bird in North America. 

Mourning Dove Scientific Name

The mourning dove (Zenaida macroura) is a member of the dove family, Columbidae. 

Other Names

The bird is also known as the American mourning dove, the rain dove, and the turtle dove, and it was once known as the Carolina pigeon and Carolina turtledove.

Mourning Dove Meaning

While the mourning dove is often a symbol of sorrow and mourning, it symbolizes the same things as its white dove cousin. The mourning dove is, above all other symbolism, a spiritual messenger of peace, love, and faith. A reflection of grief is evoked by their sound.

Mourning Dove Life Spans

It is estimated that between 50-65% of all Mourning Doves die annually. The average life span for an adult Mourning Dove is 1.5 years. The oldest known free-living bird, discovered through bird banding research, was over 31 years old.

Mourning Dove Nest

Typically mourning dove nests made in amid dense foliage on the branch of an evergreen, orchard tree, mesquite, cottonwood, or vine. Also quite commonly nests on the ground, particularly in the West. Unbothered by nesting around humans, Mourning Doves may even nest on gutters, eaves, or abandoned equipment.

Mourning Dove Eggs

A female adult mourning dove lays two plain, white, nondescript eggs per clutch. Both parents incubate the eggs for about 14 days. The parents may go on to have up to five or six broods of baby mourning doves in one season.

Mourning Dove Male vs Female

The female mourning dove has a rounder head compared to the male. The male also has a more intense and vivid coloration than the female. The male mourning dove has a peculiar bluish-gray crown, light pink breast area, and bright purple-pink patches on the sides of the neck.

Mourning Dove Behaviour 

Mourning doves sunbathe or rain bathe by lying on the ground or a flat tree limb, leaning over, stretching one wing, and keeping this posture for up to twenty minutes. These birds can also water bathe in shallow pools or birdbaths. Dustbathing is common as well. 

During sleep, the head rests between the shoulders, close to the body; it is not tucked under the shoulder feathers as in many other species. During the winter in Canada, roosting flights to the roosts in the evening, and out of the roosts in the morning, are delayed on colder days.

Mourning Dove Migration

Most mourning doves migrate along flyways over land. Birds in Canada migrate the farthest, probably wintering in Mexico or further south. Those that spend the summer further south are more sedentary, with much shorter migrations. At the southern part of their range, Mourning Doves are present year-round.  

Spring migration north runs from March to May. Fall migration south runs from September to November, with immatures moving first, followed by adult females and then by adult males. Migration is usually during the day, in flocks, and at low altitudes.


The Mourning Dove is the most widespread and abundant game bird in North America. Every year hunters harvest more than 20 million, but the Mourning Dove remains one of our most abundant birds with a U.S. population estimated at 350 million.

Saturday, 28 May 2022

Cuckoo–hawk mimicry? An experimental test

We found clear differences in tit responses depending on the mounted species to which they were exposed. During the presentations of the two harmless controls, a familiar collared dove and a novel teal, the tits often continued to visit the feeders, and afterward their attendance returned to pre-exposure levels. By contrast, they avoided the feeders during and after both sparrowhawk and cuckoo presentations. The most striking result from experiment 1 was that the response was similar to sparrowhawks and cuckoos, even though cuckoos are of no threat to adult tits. 

The plumage manipulations in experiment 2 suggested that the strong alarm response to cuckoos depended on their resemblance to hawks because when their hawk-like underpart barring was obscured, the tits treated them as no more of a threat than doves. This supports the idea that the evolution of barring in parasitic cuckoos, revealed by the comparative analysis (Payne 1967; Kru¨ger et al. 2007), enhances their resemblance to hawks. 

However, underpart barring cannot be the only feature inducing an alarm response because the tits showed equally strong alarm to barred and unbarred hawks. Furthermore, little alarm was shown to barred doves. Therefore, the underpart barring must combine with other cuckoo features, for example, their grey upperparts and elongated wings and tail, to cause hawk resemblance. We found no significant effect of the specimen, which suggests that these results cannot be attributed to any peculiarities of the particular mounts we used. 

We also found no effect of the study site, so the tits on Wicken Fen, which would have experienced daily encounters with cuckoos during the previous summer, had equally strong responses to cuckoos as the tits in Cambridge and Madingley Wood, which were unlikely to have encountered cuckoos. This suggests that the strong effect of the cuckoo at both sites was not simply one of alarm to a novel stimulus. Tits attending rich food sources are especially vulnerable to attack because sparrowhawks learn that these are good locations for finding prey (Hinsley et al. 1995). 

Because sparrowhawks make surprise attacks (Newton 1986; Cresswell 1996), alarm to any hawk-like stimuli is likely to be adaptive, despite the loss of feeding time from frequent false alarms. Nevertheless, the 5 min exposure of the specimens gave the tits ample opportunity for close inspection, so it is remarkable that a cuckoo caused a strong alarm response, given that it lacks a hawk’s lethal weapons, namely talons and a hooked beak. If the inspection of a potentially dangerous predator is costly, then even a slight resemblance through shape, grey upperparts, and underpart barring may be sufficient to deter approach. 

Other studies have shown that mimics do not have to resemble the model perfectly to gain protection, especially when signal receivers regard the model as highly noxious or dangerous, or if the model is relatively common (Ruxton et al. 2004). Perhaps the tits’ response depends not only on the stimulus but also on the context; cuckoos are absent in winter so hawk-like stimuli at this time are more likely to be hawks. 

The motivation of the signal receiver (value of the resource it is exploiting) may also influence responses to models and potential mimics (Barnett et al. 2007; Cheney & Coˆ te´ 2007). For example, it may pay a more hungry tit to risk a closer inspection of hawk-like stimuli when there is the potential for the stimulus to be a harmless mimic. Previous work on egg discrimination has shown that both great and blue tits, like other species with no history of cuckoo parasitism, will accept eggs unlike their own. This suggests that the egg rejection exhibited by cuckoo hosts has evolved specifically in response to cuckoo parasitism (Davies & Brooke 1989; Moksnes et al. 1991). 

Our results here show that, at least in one context, great and blue tits respond to adult cuckoos as if they were hawks. This raises the possibility that the discrimination by cuckoo hosts of the adult cuckoo as an enemy distinct from hawks, which can be attacked (Moksnes et al. 1991; Duckworth 1991;Welbergen & Davies in press), is also an evolved response to cuckoo parasitism. 

Experiments have revealed that in response to brood parasitism, hosts pay closer attention to the features of their own eggs so they are better able to discriminate against foreign eggs (Rothstein 1982; Lotem et al. 1995). Similarly, hosts may pay closer attention to multiple features of hawks so they can better discriminate cuckoos. Further studies are now needed to test the features used by cuckoo hosts to distinguish cuckoos from hawks and to test whether, despite some host discrimination, parasitic cuckoos still gain from hawk resemblance. Just as host improvements in egg discrimination have been selected for better cuckoo egg mimicry (Brooke & Davies 1988), so perhaps have improvements in their plumage discrimination selected for better cuckoo–hawk mimicry. 

The study followed the guidelines for the treatment of animals in behavioral research and teaching (Association for the Study of Animal Behaviour). The mounted specimens were obtained from licensed taxidermists. We thank Chris Thorne and the Wicken Fen Group, Nancy Harrison, Julia Mackenzie, and Camilla Hinde for color-ringing tits; Jan Davies for making the barred/unbarred underparts for the mounts; John Parker, the director, for permission to work in the Cambridge University Botanic Garden; two anonymous referees for their helpful comments and the Natural Environment Research Council for funding.

N. B. Davies* and J. A. Welbergen

Monday, 9 May 2022


GIANT GROUND SLOTH Giant Ground Sloth—The human silhouette in this picture gives an idea of how huge these extinct sloths were. They could even rear up on their hind legs to reach lofty food. (Natural History Museum at Tring) Giant Ground Sloth—The ground sloths were perhaps the most impressive of all the extinct South American mammals. 

Scientific name: Megatherium americanum

Scientific classification:

Phylum: Chordata

Class: Mammalia

Order: Pilosa

Family: Megatheriidae

When did it become extinct? The last giant ground sloths are thought to have died out

around 8,000 to 10,000 years ago.

Where did it live? The giant ground sloths were found throughout South America.

The largest species (Megatherium americanum), the one depicted here, was about the same size as a fully grown elephant. South America is probably the most biodiverse landmass on earth, yet, many thousands of years ago, the fauna of this continent was even more remarkable. A perfect example of this long-gone South American fauna is a ground-dwelling sloth that was the same size as an elephant. This was the giant ground sloth, and it was an immense and unusual animal. 

Fully grown, the giant ground sloth was about 6 m long and estimated of its weight range between 4 and 5 tonnes. Several skeletons (real and copies) of this animal are to be found in museum collections around the world, and one of the most astonishing things about these remains is the size of the bones. The limb bones and their supporting structures are massive and give an impression of a heavy, powerful animal. In life, the digits of the animal were tipped with long claws, which may have been used to grab plant food or even as weapons. 

We know from the skeletons of this animal that the bones of the hind feet were arranged in a very peculiar way, making it impossible for the living animal to place its feet flat on the ground. The animal could certainly rear up onto its hind legs, and perhaps even manage to amble around in this posture, using its thick tail as a strong prop, but it had to shuffle around on the outside of its feet with the long claws pointing inward. The giant ground sloth may have been able to make better progress on all fours, possibly reserving its two-legged stance for feeding or defense. 

As the giant ground sloth is related to the living sloths, it was always assumed that they were gentle plant-eating animals, but some recent, controversial scientific research has shed some light on how this massive beast used its forelimbs. These studies suggest the forelimbs of a giant ground sloth were adapted for fast movement. Such an ability was of little use to a plant-nibbling animal that needed a strong, sustained pull to bring tasty leaf-bearing branches within reach of its mouth. The research suggests that the muscles of the forelimbs were used to power the large claws into other animals, and maybe not only in defense. 

The animal’s teeth also give intriguing insights into the way it fed. They are not the normal grinding blocks that are found in the mouths of plant-feeding mammals. Th ey and the jaws they sit in appear to be adapted for slicing, much like the jaws and teeth of meat-eating animals. The claws and teeth of this giant mammal have led some people to suggest that the giant ground sloth was not a plant feeder at all, but a scavenging animal that used its size to drive predatory animals from their kill before digging into the carcass. 

The image of a 5-tonne brute ambling over to a group of dire wolves, scaring them off, and then devouring their kill is quite fantastic. Regardless of this research, it is decidedly unlikely that this giant lived in this way, and like its living relatives, the giant ground sloth was probably a herbivore, but it may have been able to use its forelimbs and teeth to defend itself. As with almost all of the long-dead animals that once roamed South America, we cannot be certain what brought about the demise of the giant ground sloth. It has been speculated that the arrival of modern humans, with spears and arrows, led to their extinction, but it is reasonable to assume that there was something much more far-reaching happening at the time that wiped these animals out. 

Climate change is one of the usual suspects, and we know that the earth’s habitats were going through some massive changes at the time these animals went extinct. Global temperatures were changing, and land-dwelling animals everywhere were being affected. Hunting may have had an effect, but it may have been minor compared to the ravages of climate change. Today, there are still vast areas of South America where people rarely venture, and some people believe that a species of giant ground sloth may have somehow survived the events that wiped out its relatives and is alive and well in these remote areas. 

Local inhabitants call the beast the mapinguary, and it is said to rear up on its back legs and emit a foul-smelling odor from a gland in its abdomen—not only that but the creature is said to be impervious to bullets and arrows, thanks to some very tough skin on its belly and back. Without a specimen or an excellent photograph, it is difficult to take these stories seriously, but it is worth remembering that previously unknown species of mammal are discovered fairly regularly, and some of them are surprisingly large. If a live giant ground sloth was found today, it would be the zoological story of all time. 

• It is thought that there were around four species of giant ground sloth. The species mentioned here (Megatherium americanum) was by far the biggest. The closest living relatives of these extinct animals are the anteaters, armadillos, and tree sloths. The biggest of these, the giant anteater, would be dwarfed by even the smallest giant ground sloth.

• In 1895, a rancher by the name of Eberhardt found some hide in a cave in Patagonia that turned out to be giant ground sloth skin. The skin was in very good condition, and some people believed that it was from an animal that died relatively recently. When techniques became available to age the skin, it was found to be several thousand years old—it was just that the very dry conditions in the cave had prevented it from rotting. Interestingly, the mummified skin was studded with bony nodules, which probably gave the animal excellent protection from the teeth and claws of predators, and perhaps even the spears and arrows of early humans. 

• It would be fantastic if a species of giant ground sloth had somehow survived into the modern-day, but accounts of the mapinguary may be due to confusion with other animals or derived from folk memories of when humans encountered these animals thousands of years ago.