The genus Corvus contains the Ravens, Crows, Rooks and Jackdaws. Seven species are found in India, several of which are divisible into well-marked geographical races, some of which were ranked by Oates as species whilst others equally easily differen¬tiated were altogether ignored. Of the seven species some are widely distributed and well known to all, and others are confined to the Himalayas and the north-west portion of the Empire.
Corvus has the plumage black throughout or nearly through¬out, and may be recognized by the position of the nostrils, which are placed far forward, about one-third the length of the bill from the forehead, and are entirely concealed from view by a multitude of very stiff, straight bristles that reach the middle of the bill. In these characters this genus agrees with the Magpies; but the latter may be separated by the length of the tail, which is very much longer than the wing, and the shape of the first primary, which is figured on p. 37.
The Crows are with two exceptions resident, the other two being only winter visitors.
The Rook forms a partial exception to the general characters given above for determining Corvus. Up to nine months of age it has the ordinary stiff bristles over the nostrils, but at that age it casts them all off, as well as the feathers on the front part of the head. Its appearance in this state is well depicted in the figure of the head given on p. 31.
Key to Species.
A. Size large, wing always oyer 380 mm C. corax, p. 21.
B. Size smaller, wing always under 380 mm.
a. Crown and neck con-colorous or nearly so.
a1. Lower plumage with little gloss, and this blue or green; bill stout, face feathered in adults.
a2. Plumage intensely black, feathers of hind neck firm and glossy with
glistening shafts C. corone, p. 24.
b2. Plumage not so black, feathers of hind neck soft and decomposed with in-
conspicuous shafts C. coronoides, p. 25.
b1. Lower plumage intensely glossed with blue and purple, bill slender, face of
adults bare C. frugilegus, p. 30.
b. Hind neck grey or ashy, contrasting with black crown.
c1. Wing exceeding 300 mm C. cornix, p. 32.
d1. Wing never as much as 300 mm.
c2. Chin and throat deep black contrasting
with breast ,, C. splendens, p. 32.
d2. Chin and throat grey like breast .... C. monedula, p. 36.
Key to Subspecies.
A. Plumage glossy black, the brown tint if
present almost imperceptible.
a. Wing averaging about 420 mm. Bill about
71 mm. Throat-hackles short C. c. laurencei, p. 21.
b. Wing averaging about 500 mm. Bill about
81 mm. Throat-hackles long C. c. tibetanus, p. 23.
B. Plumage very brown on neck, upper back and
scapulars C.c.. ruficollis, p. 23.