Black Tern 25 
Black Tern. Hydrochelidon nigra surinamensis. 
A.O.U. Checklist no 77—Colorado Records—Aiken 72, p. 210 
Coues 74, p. 708 ; Drew 83, p. 18 ; Morrison 89, p. 147 ; Cooke 97, p. 52 ; 
Henderson, 03, p. 234; 09, p. 225; Warren 08, p. 20. 
Description.—Adult in summer—Head and nape all round and under- 
parts to the vent jet black ; under tail-coverts white ; above from the 
nape silvery grey, a little duskier on the primaries ; iris brown, bill 
black, feet reddish-brown. Length 8°5; wing 8°30; tail 3°40; culmen 
1:0; tarsus °65. 
In winter the black of the head and under-parts is replaced by white, 
but the hind half of the crown is dusky grey and there is a dusky bar 
from the ear-coverts to the eye; above as in the summer, but many 
of the feathers edged with whitish. Young birds resemble the winter 
adults but have a good deal of brown about the scapulars and a marked 
black crescent in front of the eye. 
Distribution.— Breeding from the middle states from Kansas and 
Illinois north to Hudson Bay and Alaska ; south in winter as far as 
Chili and Brazil. Along the Atlantic coast on migration only. 
The Black Tern is a not very uncommon summer resident in, Colorado, 
breeding in communities where suitable conditions occur, chiefly in, 
the eastern plains portion of the State. It is probably still more 
common on migration. Coues saw a large colony on the Arkansas 
River near Fort Lyon on, June 10th, 1864, which were probably breeding, 
and there are eggs in the Colorado College Museum presented by 
I. C. Hall, and taken by him on Storms Lake near Greeley, May 26th, 
1902. There are a few birds on Barr Lake and several single nests 
have been taken by Hersey and Rockwell. Other references are El 
Paso co. (Aiken), Boulder co. plains (Henderson), and Bear Lake 
near Steamboat Springs in Routt co., where Warren saw a dozen 
or fifteen flying about, June Ist; this is the only definite record 
from the western slope. 
Habits.—The Black Tern is usually seen in flocks 
of larger or smaller size, flying over or near water, either 
a river, lake or marsh. “The flight is buoyant in the 
extreme,” says Coues, ‘and wayward, desultory and 
uncertain ; perhaps no bird of this country has so great 
an expanse of wing for its weight, certainly none fly 
more lightly. In hovering along on the look-out for 
insects, they hold the bill pointing straight down like 
other Terns. In the spring I have observed them plunging 
