COLUMBA LEUCOCEPHALA. 
333 
seldom exceeding twice its width in length. The marginal indentations are four but the 
two inner are often inclosed and do not occupy more than one third of the length of the 
sternum. The keel is high and extends nearly or quite the entire length of the sternum. 
There is no manubrium. The furcula is short and weak. Scapula, not truncated but 
pointed. The oesophagus is dilated into a large double crop which, during the nesting sea¬ 
son, is provided with a coating of glands from which exudes a kind of milky fluid which is 
mixed with the macerated grain, and the young are fed with the mixture by regurgita¬ 
tion. This crop is supported by a muscle which extends from the middle to the skin of 
the neck. The sterno-trachealis is not especially strong and there are one or two pairs of 
other laryngeal muscles which, however, do not extend over all the half rings. The tym- 
paniform membrane is present but there is no semilunar membrane, although there is an os 
transversale. The proventriculus is remarkably well developed. The stomach is very 
muscular and is lined with a.hard, rugose membrane. The fold of the duodenum is not 
long and incloses a large double pancreas. The intestines are quite small and long but 
the coeca is either absent or very small. The tail is either square, rounded, or pointed 
but never forked. The eggs are seldom more than two in number and the young, when 
first hatched, are naked. 
FAMILY I. COLUMBIDiE. THE DOVES. 
The sternum is wide, exceeding one half the length. The tip of the keel is considerably 
rounded. 
The size is usually large. Head, small. The tail has either twelve or fourteen feath¬ 
ers and the tarsus is slightly feathered in front. This is a large family and the members 
are generally distributed throughout the world. 
GENUS I. COLUMBA. THE DOVES. 
Uen. Ch. Bill, rather short and stout. Tail, short, and rounded or square. Sternum, rather narrow. Coeeca, mod¬ 
erately well developed. 
Members of this genus are quite large, rather dull in color, but occasionally have some conspicuous white markings. 
There is but one species within our limits. 
COLUMBA LEUCOCEPHALA. 
White-headed Dove. 
Columba leucocephala Linn. Syst., Nat., I; 1766, 281. 
DESCRIPTION. 
Sp. Cir. Form, robust. Size, quite large. Sternum, stout. Tongue, long, rather thin, broadening toward tip which 
is horny and pointed. Coeca, small. Tail, rounded. 
Color. Adult male. General color throughout, dark slaty-blue, becoming very dark on the tail above and black be¬ 
neath. Top of head, from bill to nape, pure white, margined behind with bluish which rapidly becomes rich purplish- 
brown on the hind neck. The neck on sides' and lower portions is iridescent green, with golden reflections, while each 
feather is margined with black. 
Adult female- Quite similar to the male, but differs in having the white head slightly overwashed with dusky and the 
remaining colors somewhat duller. 
Nestlings. Are at first nearly black, then gradually assume the adult plumage. Bill, red, bluish-white at tip, feet, 
purplish-red, and iris, yellowish-white, in all stages. 
