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Raven
Aggressive and unwary, the Common Raven is a ubiquitous habitat
generalist. Throughout their range, they inhabit montane areas but may be
found in virtually every type of forest, as well as among man-made structures.
At 61cm, these birds are the largest of the passerines (perching birds). Characteristic
traits include their long, wedge-shaped tails, long, powerful bills and thick,
shaggy throat feathers. Their long, rounded wings extend nearly to the tips
of their tails! While the sleek plumage of the adult is completely black,
it has a bluish, iridescent sheen in the sunlight. Juvenile birds display
gray-based neck feathers. On the fly, Common Ravens soar, flapping only occasionally
(distinguishing them from crows that never soar).
They are very common in the Upper Peninsula.
The noisy Common Raven has a remarkable variety of vocalizations. Their sounds
range from deep, baritone croaks to high bell-like, twangs. Typical calls
include a long, hoarse "kraaah," a lower, hollow "brrronk"
and a deep, resonant "prruk," although their repertoire is much
more extensive.
Nests are built on cliffs or conifers and occasionally in deciduous
trees or human-constructs. Over several weeks, both parents assemble the bulky,
bowl-shaped nests of branches and twigs and line it with bark and hair. Nests
may be repaired and reused perennially. Clutch size varies from 3-7, 50mm,
greenish eggs, marked in browns and olives. The female alone incubates the
clutch for 18-21 days but the male feeds her during this time. Young birds
fledge in another 38-44 days. Both parents assist in rearing the young.
Common Ravens are omnivorous foraging generalists, particularly fond of carrion
and garbage. Their powerful bill enables them to feed on carcasses, small
vertebrates, bird eggs, nestlings, insects, invertebrates (mollusks), seeds
and fruits. These intelligent birds are known to temporarily cache buried
food, hunt cooperatively in groups and post a sentinel when feeding. As ground
gleaners, they forage by picking prey and food from the ground and vegetation
as they walk (rather than hop).