Northwestern Crow Life History

Habitat

Habitat Open WoodlandsNorthwestern Crows live near the coast and forage along bays, tidepools, and river deltas. They are also increasingly common in villages, towns, and campgrounds. They also nest on coastal islands, but typically move to the mainland for winter. Northwestern Crows are not often found in deep forest.Back to top

Food

Food OmnivoreLike most crows, Northwestern Crows are omnivores. They eat marine and terrestrial invertebrates, seize fish from tidepools, catch snakes, amphibians, small birds, and small mammals, steal bird eggs and nestlings, and also take fruit, seeds, garbage, and carrion.Back to top

Nesting

Nest Placement

Nest TreeNorthwestern Crow pairs visit several sites before choosing where to nest. Typically this will be in the interior of a tree or shrub, in a blackberry tangle, or on the ground against trunks, in grasses along cliffs, or under tree trunks.

Nest Description

The nests of Northwestern Crows are made of branches that range up to a foot in length. The female is the primary nest builder, but the male accompanies her as she works. When they nest on the ground, Northwestern Crows use just a few branches or twigs to make the nest exterior. The nest cup is made of grass, moss, soil, strips of bark, feathers, and leaves. Nests are about a foot across and 9 inches deep, with an inner cup about 6 inches across and 4 inches deep.

Nesting Facts
Clutch Size:3-6 eggs
Number of Broods:1 brood
Egg Length:1.6 in (4 cm)
Egg Width:1.1-1.1 in (2.8-2.9 cm)
Incubation Period:17-20 days
Nestling Period:29-35 days
Egg Description:Blotchy pale green, blue, and gray.
Condition at Hatching:Blind and helpless; minimally covered in down.
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Behavior

Behavior Ground ForagerNorthwestern Crows often walk along the ground to forage. In flight, they have regular wing beats but sometimes glide or soar on their strong wings. While breeding pairs are monogamous and may stay together for several year, extra-pair copulation is common. In winter, Northwestern Crows of all ages roost together in a complex hierarchical system. Flocks communicate through a variety of signals and sounds, gathering quickly to mob predators. Like some other members of the crow family, they've also been seen "playing," by dropping and catching in midair a small item such as a twig.Back to top

Conservation

Conservation Low ConcernNorthwestern Crow is common, but populations may have experienced a decline between 1966 and 2015, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 800,000 with 43% living in the U.S., and 57% in Canada. The species rates a 9 out of 20 on the Continental Concern Score and is not on the 2016 State of North America's Birds' Watch List. Back to top

Credits

Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.

Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.

Verbeek, N. A. and Robert W. Butler. 1999. Northwestern Crow (Corvus caurinus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

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