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Northwestern Crow - BirdForum Opus

Revision as of 13:34, 9 March 2010 by Wintibird (talk | contribs) (reference added)
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Photo by jvhigbee
Washington, USA, January 2005
Corvus caurinus

Identification

A large (41cm length, 86cm wingspan), all-black bird.

  • Plumage black with purple sheen on head, neck, wing, tail and back
  • Dark brown iris
  • Glossy black bill
  • Medium-length tail

Sexes similar, males are on average larger than females. Juveniles are dull black, fluffy and have a blue iris.

Similar species

Very similar to American Crow and virtually indistinguisable in the field except by range. Slightly smaller than the latter.

Distribution

Pacific Coast of North America from Puget Sound area north to Gulf of Alaska.
In many cities along the Pacific coast the populations of Crows have increased. However, it's not sure if this species or American Crow is responsible for this. If the birds in the cities are American Crows, the population of pure Northwestern Crows may be very small.

Taxonomy

This is a monotypic species.
May form a superspecies with American Crow and is known to interbreed with the latter.

Habitat

Beaches and shorelines are the principal forage areas.

Behaviour

Diet

Includes stranded fish, shellfish, crabs and mussels; it also searches through refuse containers for suitable food items. It also regularly eats insects, other invertebrates, and various fruits (especially berries). It raids other birds' nests to eat eggs and hatchlings.

Breeding

Breeding season from April to June. Nests loosely colonial. The bulky nest is made of sticks and placed in a branch fork, tree or shrub. 4-5 eggs are usually laid.

Voice

Very varied, and many types of call are made, but the most common are usually described as a high pitched caw and the sound of a cork coming out of a bottle.
A wok-wok-wok is given by a bird in flight if straggling behind the group, and various clicks and mechanical sounding rattles are also heard.

References

  1. Clements, JF. 2008. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2008. Ithaca: Cornell Univ. Press. ISBN 978-0801445019.
  2. Del Hoyo, J, A Elliott, and D Christie, eds. 2009. Handbook of the Birds of the World. Volume 14: Bush-shrikes to Old World Sparrows. Barcelona: Lynx Edicions. ISBN 978-8496553507

Recommended Citation

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