Himalayas and Greenland are generally larger with slightly larger bills, while those from warmer
regions are smaller with proportionally smaller bills.[34] Representative of the size variation in the
species, ravens from California weighed an average of 784 g (1 .728 lb), those from Alaska weighed an
average of 1 ,1 35 g (2.502 lb) and those from Nova Scotia weighed an average of 1 ,230 g (2.71
lb).[35][36][37] The bill is large and slightly curved, with a culmen length of 5.7 to 8.5 cm (2.2 to 3.3 in),
easily one of the largest bills amongst passerines (perhaps only the thick-billed raven has a noticeably
larger bill). It has a longish, strongly graduated tail, at 20 to 26.3 cm (7.9 to 1 0.4 in), and mostly black
iridescent plumage, and a dark brown iris. The throat feathers are elongated and pointed and the
bases of the neck feathers are pale brownish-grey. The legs and feet are good-sized, with a tarsus
length of 6 to 7.2 cm (2.4 to 2.8 in).[38][39] Juvenile plumage is similar but duller with a blue-grey
iris.[40] Apart from its greater size, the common raven differs from its cousins, the crows, by having a
larger and heavier black beak, shaggy feathers around the throat and above the beak, and a wedge-
shaped tail.[41 ] Flying ravens are distinguished from crows by their tail shape, larger wing area, and
more stable soaring style, which generally involves less wing flapping. Despite their bulk, ravens are
easily as agile in flight as their smaller cousins. In flight the feathers produce a creaking sound that has
been likened to the rustle of silk.[1 9] The voice of ravens is also quite distinct, its usual call being a
deep croak of a much more sonorous quality than a crow's call. In North America, the Chihuahuan
raven (C. cryptoleucus) is fairly similar to the relatively small common ravens of the American
southwest and is best distinguished by the still relatively smaller size of its bill, beard and body and
relatively longer tail. All-black carrion crow (C. corone) in Europe may suggest a raven due to their
largish bill but are still distinctly smaller and have the wing and tail shapes typical of crows.[42]
In the Faroe Islands a now extinct colour-morph of this species existed, known as the pied raven.[43]
White ravens are occasionally found in the wild. Birds in British Columbia lack the pink eyes of an
albino, and are instead leucistic, a condition where an animal lacks any of several different types of
pigment, not simply melanin.[44]
Two Ravens Talking Mar 10 2012.ogv
Vocalising:
Common ravens have a wide
range of vocalizations which are of
interest to ornithologists. Gwinner
carried out important studies in the
early 1 960s, recording and
photographing his findings in great
detail.[45] Fifteen to 30 categories
of vocalization have been
recorded for this species, most of
which are used for social
interaction. Calls recorded include
alarm calls, chase calls, and flight
calls. The species has a
distinctive, deep, resonant prruk-
prruk-prruk call, which to
experienced listeners is unlike that
of any other corvid. Its very wide
and complex vocabulary includes
a high, knocking toc-toc-toc, a dry,
grating kraa, a low guttural rattle
and some calls of an almost
musical nature. Like other corvids,
ravens can mimic sounds from
their environment,
including
human speech.