Black Tern 25 



Black Tern. Hydrochdidon 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 imder- 

 parts to the vent jet black ; under tail-coverts white ; above from tho 

 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 liina on Storms Lake near Greeley, May 26th, 

 1902. There are a few birds on Barr Lake and several single nesta 

 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 1st ; 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 



