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Birds may be known by many common names and at times popular names are superseded by others more widely used internationally.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.

Size

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.

Identification

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.

Voice

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.

Nesting

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.

Distribution

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.

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.

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. 

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.

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.

Population

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.

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

brown-backed shrike

Contemporaneous eggs of different color types of brown-backed shrike can be smooth in the interference experiment The fertile eggs are hatched, but the out-of-phase eggs are rejected, and the basis for the judgment of the parent birds may be Egg color. There are two possible reasons for this phenomenon: one is two-color types Brown-backed shrike can distinguish out-of-phase eggs, but due to differences in the timing of ovulation Largely causes hatching and energy investment contradictions in the allocation of feeding time The second is that the two-color brown-backed shrike uses the out-of-phase eggs as parasites Egg rejection. 

Moskat & Fuisz (1999) put fake cuckoo eggs (blue Eggs with better color and imitation) are placed in red eggs during laying and early hatching. Among the back shrike nests, the coping strategies shown by the red-backed shrike include driving Eggs from abroad (71.2%), abandonment of original nests (19.2%), acceptance of foreign eggs Come eggs (9.6%), and the rejection rate of blue eggs is higher than that of eggs with better imitation; In the laying period, the eggs with better imitation are mainly abandoned, and in the incubation period.

The foreign eggs are expelled. The results of this experiment showed a phenomenon of abandoning the nest, and the performance of heterochromatic and homochromatic types is more consistent. brown-backed shrike pair nest Insensitivity to the number of mid-eggs, increased contemporaneous homochromatic eggs, or intentional or unintentional Reducing the number of eggs will not affect their nesting. But at the same time, the brown-backed shrike nest will be abandoned in the case of strong human disturbance. 

According to local villagers, the Brown-backed shrike is seen navigating the transfer of chicks in old nests during brooding to the new nest. Judging from the current situation, the white spots or white edges on both sides of the wings of birds are not It is easy to be found by natural enemies or predators, and it is easier to appear white above and below It was discovered by natural enemies, so white spots and white borders on the side of the body may play a role in the individual The effect of recognition, especially the recognition of the parent by the offspring during the feeding period. 

Book The experimental foster child chicks were nurtured normally in the foster parent's nest, and after development Follow the activities of the righteous parent and learn their behavior, its later spread and the relationship with the righteous parent The relationship needs to be further studied in the future. The sexual selection hypothesis suggests that plumage polymorphism may be due to female Preference for salient morphologies and predation pressure favoring concealed morphologies produced and maintained. In this case, the plume polymorphism reflects the relative dominance of the individual, which is correlated with the expression of bodily signals Consistent, that is, the degree of pigmentation represents different status, such as health and nutritional status. 

However, prominent patterns favorable to sexual selection may be due to high predation risk or used to produce and maintain significantly high color energy expenditure and balance with non-salient forms (Endle, 1980). A total of 21 brown type, 9 black type, and heterozygous type were found in the plot. 10, including 10 heterozygous nests, 6 black-type females, many The species-colored brown-backed shrike breeds synchronously, and there is no preference for the same species of shrike The opposite sex is paired. In summary, we included in 2006-2008 The 44 nesting birds found in the plot were brown and black broodstock. 

In the breeding nest, the ratio of black-type females to brown-type females was 20:24. From the perspective of the sexual selection ratio, the ratio is similar, and there is no large ratio. That is, females show no preference for males of different color types. from reproduction From a physical point of view, we have not been able to determine the brown-backed shrike feather machine control, maybe plumage polymorphism is not related to selection, it may be simply a neutral relationship to a physiological or ecological characteristic or non-adaptive traits (Galeotti, 2003) Both color types are absent in both reproduction and brooding during the reproductive process Isolation occurs. 

The generally accepted concept of species holds that a species is Nature is able to mate, produce fertile offspring, and exist with its population reproductively isolated groups. Integrated reproductive isolation and morphological traits, behavior Evidence of differentiation, we support that black shrike is just one of the brown-backed shrikes Chromotype, rather than an independent species point of view. About Black Type Source and Feather Color Genetic laws and other issues still need to be investigated in the future for more different types of brown. 

The accumulation of research on Shrike individuals, from morphological, ecological, genetic Comprehensive research in multiple disciplines such as science and geography. Acknowledgments: Jiang Yanqiong assisted in the completion of the control experiment of easy eggs and easy chicks work, the Guangdong Haifeng Bird Nature Reserve provided the Thank you for your help!

Dark-throated Oriole (Oriolus xanthomas)

 Size: About that of the Myna.

Field Characters:

Dark-throated Oriole is a species of family Oriolidae. The brilliant golden-yellow bird has a jet-black head, throat, and upper breast. It has black in wings and tail, as sexes alike. It is found singly or in pairs, arboreal, in wooded country.

Distribution:

The whole of the Indian empire expected the arid portions west of a line from Kathiawar through Mount Aboo to the Sutlej Kiver. In the Himalayas, the bird can be found up to about 4,000 ft. Three races are recognized for differences in size and details of coloration, viz., the largest northern xanthornus, the intermediate peninsular maderaspatanus, and the smallest Ceylonese ceylonensis. It is resident over the greater part of its range but also moves about locally to some extent.

Habits:

This oriole, like the last, is a bird of well-wooded country and groves of large trees, often in the neighborhood of human habitations. It has a variety of loud melodious calls which in general are very like those of the Indian Oriole. A harsh monosyllabic note commonly uttered is mistaken for one of the Tree-Pie's. Otherwise, there is no appreciable difference between the habits of the two species. The natural habitat of this oriole is subtropical or tropical moist lowland forests.

Nesting:

The principal months in India are from April to July, but in Ceylon, it apparently breeds from October to May. The structure and size of the nest do not differ from those of the Indian Oriole, but the eggs are somewhat smaller, pinker, and less glossy. Orioles of both species, along with such other mild-mannered birds as doves and babblers, often build in the same tree as holds a nest of the Black Drongo.

That this is by design rather than accident can scarcely be doubted considering how frequent the occurrence is. It is certain also that the birds must thereby enjoy a degree of protection against marauders like crows and tree-pies. King Crow will tolerate the proximity of his harmless dependents with complacence, but a crow has only to show himself in the precincts of the nest tree to be furiously set upon and beaten off by the valiant kotwal and his wife.

Other Names

The other names of Dark-throated oriole are black-throated oriole, black-headed oriole, and Malaysian oriole. Also, the black-headed oriole shouldn’t be confused with the species of a similar name, (Oriolus larvatus).

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