9. Pavo cristatus.
THE COMMON PEA-FOWL. Cristatus
formed with a tuft or crest, crista.
Mor, India; Mujur, Terai; Myl (Tamil); Nimili (Telegu); Nowl (Canarese); Monara, Ceylon; Moir, Assam; Mabja (Bhutia); Mong-yung (Lepcha); Dode, Garo Hills.
Male 42" to 48" to end of true tail, train 40" to 48" ; 9 to 11 1/4 lbs. Female 36" to 40", tail 12" to 15"; 6 to 8 1/2 lbs. Legs grey-brown. Bill horny brown. Facial skin white. Crest of twenty-four feathers, naked shafts, webbed at tips. Head, neck, and breast purple. Above green. Lesser and median wing-coverts, shoulder-feathers and inner secondary quills buff, barred and mottled black, glossed green. Primaries and tail chestnut. Train green. Thighs buff. Abdomen black.— Female: Head and nape chestnut. Above light brown, with faint wavings. Tail light brown, tips white.
" Cases of gradation are important, as they show that it is at least possible that highly complex ornaments may have been acquired by small successive steps."—Darwin.
The feathers of the Peacock are excellent examples of gradation in ornament, showing a gradual transition from a comparatively plain and simple feather merely marked with alternate dark and light bands and having no metallic lustre into the elaborate and gorgeous " eye-bearing " feather, one of the most beautiful objects in the world. Similarly there is a retrograde transition from the fully developed eye-bearing form of the elongated central tail-coverts to the curiously modified feathers which complete the margin of the train. The terminal portion of one of the tail-coverts shows the beautifully coloured ocellus or eye surrounded above by the "transparent zone," an effect produced by the absence of the barbules on a limited portion of each of the barbs.
The Common Pea-fowl is distributed throughout India and Ceylon, ascending the Himalayas to 2,000 feet and the hills in Southern India to 5,000 feet. It inhabits the whole Assam valley up to Sadiya, but none are found in Sylhet,, Cachar, or Manipur. Males moult about September in N. India, and the train is not fully grown till April. Six or fifteen eggs (2.74 x 2.05), unspotted, glossy, closely pitted, white to reddish buff in colour. (J. 803. B. 1324.)
Also P. nigripennis, the Black-shouldered P. F,, differing from P. cristatus in having the lesser and median wing-coverts, shoulder-feathers, and inner secondary quills brownish black. Hitherto only observed among birds in captivity, and supposed to be a reversion to the ancestral type. It is not known if this form ever occurs among wild Indian birds. (O.G. ii. 81.)