308 Birds of Colorado 
Whether the birds on the west side of the Divide should he referred 
to this or some other subspecies cannot at present be definitely decided. 
Habits.—The Red-winged Blackbird is an exceedingly 
gregarious and sociable bird. It is nearly always found 
in large flocks except during the breeding season, and 
even then it nearly always breeds in companies. In 
the early spring the two sexes usually form separate 
troops. During the greater part of the year its food 
consists almost entirely of the seeds of various plants 
and weeds, but in June, while the young are being reared, 
large quantities of insects, chiefly beetles and grass- 
hoppers, are eaten. In July and August it resorts to the 
grain-fields, and when in Jarge numbers does a considerable 
amount of damage, chiefly to the oat crops. 
It seldom nests far from water—generally among reeds 
or rushes growing in swamps or sloughs. The nest is 
a large one, constructed of coarse grasses woven wet, 
and lined with finer material of the same sort. It is 
generally a foot or two above the water. Four is the 
usual number of eggs; these are pale greenish, spotted 
and blotched with various shades of brown and purplish. 
They average 98 x ‘69. Only one brood is raised in 
the season, and the males appear to be polygamous, 
a small colony often containing only one cock. 
Northern Redwing. <Agelaius pheniceus fortis. 
A.O.U. Checklist no 498d. 
Description.—Closely resembling A. pheniceus, but distinctly larger 
and with a stouter and relatively shorter bill. Length 9-0; wing 5-0; 
tail 3-8; tarsus 1:19; culmen -80. 
The female is correspondingly larger than the female of the typical 
form ; wing 4-15. 
Distribution.—This subspecies, recently discriminated by Ridgway, 
breeds in the interior districts of British America, on the Mackenzie 
River and in Athabasca. It migrates south in winter through the 
westorn half of the Mississippi Valley as far south as western Texas 
and Arizona. The Redwings which winter in Colorado in considerable 
