Pied crow

Pied crow
In Etosha National Park, Namibia
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Aves
Order:Passeriformes
Family:Corvidae
Genus:Corvus
Species: C. albus
Binomial name
Corvus albus

The pied crow (Corvus albus) is a widely distributed African bird species in the crow genus. Like most crows and ravens, it is an adaptable, generalist species with a broad diet. Its plumage is a striking black and white, somewhat resembling its much larger relatives the thick-billed raven and white-necked raven; unlike these ravens, it also has a white belly.

Description

It is approximately the size of the European carrion crow (46–52 cm in length) but has a longer 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, but the tail, bill and wings are black. The eyes of a fully matured bird are dark brown. The white plumage of immature birds is often mixed with black. It resembles the White-necked and thick-billed ravens but is much smaller, less stocky and has a smaller bill.[2]

Structurally, the pied crow is better thought of as a small crow-sized raven (although it exhibits some crow-like traits such as a lack of throat hackles and a fan-shaped tail), especially as it can hybridise with the Somali crow (sometimes called the 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.

Measurements

  • Length 46 – 52 cm [3]
  • Wingspan 85 to 98   centimetres (17 unsexed birds)[3]
  • Weight 520g [3]

Identification

In southern Africa the range overlaps with the white-necked raven. The pied crow is 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.[4]

Vocalisation

The voice is described as a harsh "ar-ar-ar-ar" or "karh-karh-karh" and lacks the whispering note of the White-necked raven.[5]

Taxonomy

The pied crow was first described in 1776 by Statius Muller. Its specific name is the Latin adjective albus, meaning "white". Recent findings indicate that based on mitochondrial DNA, common ravens (C. corax) from the north of the United States are more closely related to those in Europe and Asia than to those in the California clade, and that common ravens in the California clade (C. corax sinuatus) are more closely related to the Chihuahuan raven (C. cryptoleucus) than to those in the Holarctic clade.[6] while ravens in the Holarctic clade are more closely related to the pied crow (C. albus) than they are to the California clade.[7] Thus, the common raven species as traditionally delimited is considered to be paraphyletic.[7]

Distribution and habitat

This species, Africa's most widespread member of the genus Corvus, occurs from Sub-Saharan Africa, specifically Senegal, Sudan, Somalia and Eritrea down to the Cape of Good Hope and on the large island of Madagascar, the Comoros islands, Aldabra group islands, Zanzibar, Pemba and Fernando Po. Although the species is still a vagrant north of the Sahara, a breeding case [8] and a number of long-staying birds [9][10] were observed during the last few years in Morocco. 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]

Behaviour

Pied crows are generally encountered in pairs or small groups, although an abundant source of food may bring large numbers of birds. The species behaves in a similar manner to the hooded and carrion crows.[11] In Dakar, birds have been observed mobbing passing ospreys and snake eagles but avoiding black kites.

Diet

All of its food is obtained from the ground 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 sometimes fruit and even mushrooms.[12] It has been recorded killing and eating roosting bats and is frequently seen scavenging around slaughterhouses in large numbers.

Reproduction

The nest is usually built in tall, isolated trees, though sometimes smaller ones are used, depending on availability. The cross supports of telephone poles are also frequently used, and both sexes build the nest. A clutch of 3–6 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.[11]

References

  1. ↑ BirdLife International (2013). "Corvus albus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. 1 2 Goodwin, p. 132
  3. 1 2 3 Roberts' Birds of Southern Africa. The John Voelker Bird Book Fund. p. 474. ISBN 0-620-17583-4.
  4. ↑ Roberts' Birds of Southern Africa. The John Voelker Bird Book Fund. pp. 474–477. ISBN 0-620-17583-4.
  5. ↑ Goodwin, p. 134
  6. ↑ US Geological Survey. "California Ravens Are a Breed Apart". Retrieved 2007-05-11.
  7. 1 2 Feldman, Christopher R.; Omland, Kevin E. (March 2005). "Phylogenetics of the common raven complex (Corvus: Corvidae) and the utility of ND4, COI and intron 7 of the β-fibrinogen gene in avian molecular systematics". Zoologica Scripta. 34 (2): 145–156. doi:10.1111/j.1463-6409.2005.00182.x.
  8. ↑ Batty, C. 2010. Pied Crows in Western Sahara, Morocco.Dutch Birding 32: 329.
  9. ↑ MaghrebOrnitho. 2015. Pied Crow (Corvus albus) near Fnideq, northern Morocco. Consulted: 11 February 2017.
  10. ↑ MaghrebOrnitho. 2017. The resident Pied Crow at Mhamid, eastern Sahara (2015-2017). Consulted: 11 February 2017.
  11. 1 2 Goodwin, p. 133
  12. ↑ Goodwin, pp. 132-33

Cited text

  • Goodwin D. (1983). Crows of the World. Queensland University Press, St Lucia, Qld. ISBN 0-7022-1015-3.
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