Birds 61 



more or less regularly in Colorado, M. americanus being com- 

 paratively common on migration in April. 



The Anatinae, with eight genera, and the Fuligulinae, also 

 with eight genera, are the various kinds of ducks, of which twenty- 

 six species have been found in Colorado. Following the keys of 

 Sclater and Mrs. Florence Merriam Bailey, the genera are sep- 

 arated as follows. Erismatura differs from all the others by the 

 tail being more than half the length of the wing, practically with- 

 out upper coverts, the tail feathers 18. The adult male has the 

 top of the head black. The other Fuligulinae (Sea-ducks), having 

 the hind toe with a flattened membranous lobe, are separated into 

 Somateria (American Eider), with the feathering on the lores or 

 forehead extending forward well beyond the posterior border of 

 the nostril, and several genera in which this is not the case. From 

 this point on it is easier to distinguish the ducks (adult males) 

 by the appearance of the head. The Red-head (Marila americana) 

 has the whole head and neck bright reddish chestnut, but the 

 Canvas-back (M. valisineria of Wilson*) has head and neck rich 

 chestnut brown, dusky on crown and face. The other members 

 of this genus have head and neck greenish or purplish-black; 

 glossed with green in the Scaup Duck (M. marila), with purple 

 in the Lesser Scaup Duck (M. affinis) and the Ring-necked Duck 

 (M. collaris). The last is separated by the dark chestnut collar 

 on neck. The remaining members of the subfamily have con- 

 spicuous markings on the head, except the American Scoter 

 (Oidemia nigra americana), with dark plumage, but even in this 

 the swollen base of the bill is ornamented with a large yellow and 

 red spot. In the White-winged Scoter (Oidemia deglandi of Bona- 

 parte) the black head has a white patch in the region of the eyes, 

 pointed posteriorly. In the Surf Scoter (0. perspicillata) the 

 plumage is black, with a triangular white patch on forehead and 

 one on back of head.** The Harlequin Duck (Histrionicus his- 

 trionicus) is small, with a short bill, head with several white patches, 

 sides of belly bright rufous, wings with steel blue speculum and 

 four white spots. The colors are much duller in the summer 



*A. valltineria of authors. Recent authors place this bird in a distinct genus, Aristonetta. 

 **0. deglandi and 0. perspicillata are referred by some to a distinct genus, Melanitia. 



