Pied crow | |
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In Etosha National Park, Namibia | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Corvidae |
Genus: | Corvus |
Species: | C. albus |
Binomial name | |
Corvus albus Müller, 1776 | |
The pied crow (Corvus albus) is a widely distributed African bird species in the crow genus of the family Corvidae.
Structurally, the pied crow is better thought of as a small crow-sized raven, especially as it can hybridise with the Somali crow (dwarf raven) where their ranges meet in the Horn of Africa. Its behaviour, though, is more typical of the Eurasian carrion crows, and it may be a modern link (along with the Somali crow) between the Eurasian crows and the common raven.
It is about the size of the European carrion crow or a little larger (46–50 cm in length), but has a proportionately larger bill, slightly longer tail and wings, and longer legs. As its name suggests, its glossy black head and neck are interrupted by a large area of white feathering from the shoulders down to the lower breast. The tail, bill, and wings are black, too. The eyes are dark brown. The white plumage of immature birds is often mixed with black. It resembles the white-necked and thick-billed ravens, but has a much smaller bill. [2]
In southern Africa, its range overlaps with the white-necked raven. The pied crow is slightly smaller and has a white chest and belly with a black, more delicate beak compared to the black chest and belly of the larger white-necked raven, which also has a white-tipped and weightier beak. [3] It is larger than the black crow.
The voice is often described as a harsh ar-ar-ar-ar or karh-karh-karh. [2]
The pied crow was first described in 1776 by Statius Muller. Its specific name is the Latin adjective albus, meaning "white".
The Maasai people call it ol-korrok from the sound of its call. It is considered annoying, but not a bird of ill omen. [4]
This species, Africa's most widespread member of the genus Corvus, occurs from sub-Saharan Africa, specifically Nigeria, Ghana, Senegal, Sudan, Somalia, Eritrea, Zambia, Botswana, Mozambique and Zimbabwe, South Africa and on the large island of Madagascar, the Comoros Islands, Aldabra, Assumption Island, Cosmoledo, Astove Island, Zanzibar, Pemba, and Fernando Po. It inhabits mainly open country with villages and towns nearby. It does not occur in the equatorial rainforest region. It is rarely seen very far from human habitation, though it is not as tied to the urban way of life as the house crow (Corvus splendens) of Asia, and may be encountered far from human habitation in Eritrea. [2]
Pied crows are generally encountered in pairs or small groups, although an abundant source of food may bring together large numbers of birds. The species behaves in a similar manner to the hooded and carrion crows. [2] In Dakar, birds have been observed mobbing passing ospreys and snake eagles, but avoiding black kites.
All of its food is obtained from the ground, trees, etc., including injured wildlife such as insects and other small invertebrates, small reptiles, small mammals, young birds and eggs, grain, peanuts, carrion, and any scraps of human food and fruit. [2] It has been recorded killing and eating roosting fruit bats, and is frequently seen (sometimes in huge numbers) scavenging around slaughterhouses.
The small intestines within the African pied crows include duodena, jejuna, and ilea, which are vital components for nutrient absorption, such as fats, proteins, and carbohydrates consumed by the crow.
Pancreatic ducts and two bile ducts make up the duodenum, so provide greater support for nutrient digestion. [5] The wall of the small intestine is lined with four main tunics - tunica mucosa, tunica submucosa, tunica musclaris, and tunica serosa. The primary purpose of the said tunics is to protect the inner environment of the small intestine against foreign invaders that could otherwise harm the crow.
Pied crows tend to operate with restricted digestive capacity despite being capable of consuming greater than half their body weight of food per day. [6] To maintain their slender weight, these birds rely on this reduced digestive capacity to aid in food regulation to ensure they can fly swiftly. [7]
Pied crows obtain a characteristic looping and spiraling of their small intestines, which enhances their digestion and absorption of nutrients. [8] These birds also obtain restricted gut retention time for food, but to combat this, they also have increased mucosal surface area evident within their digestive tracts. [5]
The nest is usually built in tall, isolated trees, though sometimes smaller specimens are used, depending on availability. The cross supports of telephone poles are also frequently used, and both sexes build the nest. A clutch of three to six eggs is laid from September to November (depending on latitude) and are pale green spotted with various shades of brown. The eggs are normally covered when the incubating female leaves the nest. Incubation is 18–19 days and the young are usually fledged by around 45 days. Both sexes rear the young. [2]
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, magpies, jackdaws, jays, treepies, choughs, and nutcrackers. In colloquial English, they are known as the crow family or corvids. Currently, 135 species are included in this family. The genus Corvus containing 50 species makes up over a third of the entire family. Corvids (ravens) are the largest passerines.
The carrion crow is a passerine bird of the family Corvidae, native to western Europe and the eastern Palearctic.
The hooded crow, also called the scald-crow or hoodie, is a Eurasian bird species in the genus Corvus. Widely distributed, it is found across Northern, Eastern, and Southeastern Europe, as well as parts of the Middle East. It is an ashy grey bird with black head, throat, wings, tail, and thigh feathers, as well as a black bill, eyes, and feet. Like other corvids, it is an omnivorous and opportunistic forager and feeder.
The Australian raven is a passerine corvid bird native to Australia. Measuring 46–53 centimetres (18–21 in) in length, it has an all-black plumage, beak and mouth, as well as strong, greyish-black legs and feet. The upperparts of its body are glossy, with a purple-blue, greenish sheen; its black feathers have grey bases. The Australian raven is distinguished from the Australian crow, and other related corvids, by its long chest feathers, or throat hackles, which are prominent in mature birds. Older individuals and subadults have white irises, while the younger birds' eyes display blue inner rims; hatchlings and young birds have brown, dark irises until about fifteen months of age, at which point their irises become hazel-coloured, with an inner blue rim around each pupil, this lasting until they are roughly 2.5 to 3 years of age. Nicholas Aylward Vigors and Thomas Horsfield described the Australian raven in 1827, its species name coronoides highlighting its similarity with the carrion crow. Two subspecies are recognised, which differ slightly in their vocalisations, and are quite divergent, genetically.
The Torresian crow, also called the Australian crow or Papuan crow, is a passerine bird in the crow family native to the north and west of Australia and nearby islands in Indonesia and Papua New Guinea. The species has a black plumage, beak and mouth with white irises. The base of the feathers on the head and neck are white. The Torresian crow is slightly larger with a more robust bill than the morphologically similar little crow.
The forest raven, also commonly known as the Tasmanian raven, is a passerine bird in the family Corvidae native to Tasmania and parts of southern Victoria, such as Wilsons Promontory and Portland. Populations are also found in parts of New South Wales, including Dorrigo and Armidale. Measuring 50–53 cm (20–21 in) in length, it has all-black plumage, beak and legs. As with the other two species of raven in Australia, its black feathers have grey bases. Adults have white irises; younger birds have dark brown and then hazel irises with an inner blue rim. New South Wales populations are recognised as a separate subspecies C. tasmanicus boreus, but appear to be nested within the Tasmanian subspecies genetically.
The thick-billed raven, a corvid from the Horn of Africa, shares with the common raven the distinction of being the largest bird in the corvid family, and indeed the largest of the passerines. The thick-billed raven averages 64 cm (25 in) in length, with a range of 60 to 70 cm and weighs approximately 1.15 kg (2.5 lb) in females and 1.5 kg (3.3 lb) in males on average. Its size is about the same as the largest subspecies of common raven but some common raven subspecies are rather smaller and, going on average weights, the thick-billed raven is likely the heaviest extant passerine. The thick-billed raven is about 25% heavier on average than the Australasian superb lyrebird, which is sometimes erroneously titled the largest passerine.
The American crow is a large passerine bird species of the family Corvidae. It is a common bird found throughout much of North America. American crows are the New World counterpart to the carrion crow and the hooded crow of Eurasia; they all occupy the same ecological niche. Although the American crow and the hooded crow are very similar in size, structure and behavior, their calls and visual appearance are different.
The white-necked raven is a species of raven native to eastern and southern Africa. It is somewhat smaller than the common raven or its nearest relative, the thick-billed raven C. crassirostris.
The Daurian jackdaw is a bird in the crow family, Corvidae, native to eastern Asia. It is closely related to the western jackdaw. The name derives from the Dauria region of eastern Russia.
The collared crow, also known as the ring-necked crow or white-collared crow, is a member of the family Corvidae native to China and north of Vietnam.
The fan-tailed raven is a passerine bird of the crow family native to Eastern Africa and the Arabian Peninsula.
The brown-necked raven is a larger bird than the carrion crow though not as large as the common raven. It has similar proportions to the common raven but the bill is not so large or deep and the wings tend to be a little more pointed in profile. The head and throat are a distinct brownish-black giving the bird its English name, while the rest of the plumage is black glossed with purple, blue or purplish-blue. Like the common raven, thick-billed raven and white-necked raven, it is one of the larger raven species. The feathers of this species often fade quite quickly to a brownish black and the bird can look distinctly brown by the time it moults. The feet, legs and bill are black. The dwarf raven was formerly considered a subspecies but this bird now appears to be closer to the pied crow than this species.
The large-billed crow, formerly referred to widely as the jungle crow, is a widespread Asian species of crow. It is very adaptable and is able to survive on a wide range of food sources, making it capable of colonizing new areas, due to which it is often considered a nuisance, especially on islands. It has a large bill, which is the source of its scientific name macrorhynchos and it is sometimes known by the common name thick-billed crow. It can also be mistaken for a common raven. The eastern jungle crow and Indian jungle crow were once considered conspecific and together called the jungle crow.
The common raven is a large all-black passerine bird. It is the most widely distributed of all corvids, found across the Northern Hemisphere. It is a raven known by many names at the subspecies level; there are at least eight subspecies with little variation in appearance, although recent research has demonstrated significant genetic differences among populations from various regions. It is one of the two largest corvids, alongside the thick-billed raven, and is possibly the heaviest passerine bird; at maturity, the common raven averages 63 centimetres in length and 1.47 kilograms in mass. Although their typical lifespan is considerably shorter, common ravens can live more than 23 years in the wild. Young birds may travel in flocks but later mate for life, with each mated pair defending a territory.
The white-necked crow is the largest of the four Caribbean corvids. It is endemic to the island of Hispaniola ; it was formerly also extant on Puerto Rico and Saint Croix in the United States Virgin Islands, but has been extirpated from both islands due to considerable forest clearance and hunting for meat.
A crow is a bird of the genus Corvus, or more broadly, a synonym for all of Corvus. The word "crow" is used as part of the common name of many species. The related term "raven" is not linked scientifically to any certain trait but is rather a general grouping for larger-sized species of Corvus.
The Chihuahuan raven is a species of crow in the family Corvidae that is native to the United States and Mexico.
The Somali crow, or dwarf raven, is approximately the size of the carrion crow, Corvus corone but with a longer bill and a somewhat more brownish cast to the feathers, especially when worn.