Forster's Tern 23 



on the outer feathers, very long and narrow, white on the outer, dusky- 

 grey on the inner, web ; bill orange-red, dusky at the tip, legs orange - 

 red. Length 15-0 (to end of tail) ; wing 9-5 ; tail to fork 2-5, to longest 

 feather 6-0 to 8-0; culmen 1-5; tarsus -85. 



In winter the black cap is lost, but the nape is always slightly varie- 

 gated with dusky and there is a black band on either side through 

 the eye- and ear-coverts ; bill and feet duller coloured. Young birds 

 are mottled on the head and back with brownish, the prirnaries are 

 less silvery and the tail brownish and deeply emarginate, but less so 

 than in the adult. Bill srnaller and weaker and brownish-black. 



Distribution.- — Breeding locally from Texas north through the middle 

 states and Utah to Manitoba and the Fur countries and along the coast 

 to Cobb's Island, Virginia, and in CaUfornia ; south in winter as far 

 as Guatemala and BraziL 



Forster's Tern was reported as a breeding bird in Colorado as long 

 ago as 1873 by Ridgway, though no definite evidence of the fact was 

 given. In more recent years it has been observed to arrive at Loveland 

 about May 5th from the south, and Felger has found it breeding at 

 Barr Lake near Denver on May 19th, where Hersey informs me there 

 is a colony of about fifty birds in summer. It may be considered a 

 regular resident in summer in parts of north-east Colorado. 



Habits. — All the Terns have much the same habits. 

 They are all birds of swift and easy flight, coursing 

 through the air like Swallows, generally in the neigh- 

 bourhood of, or over, water. They can often be seen 

 with their heads and bills pointed downwards toward 

 the water, watching for a fish or insect. Suddenly 

 they plunge down but seldom become quite submerged ; 

 turning sharply on the surface, they rise again with the 

 morsel in their beaks. 



They nest in large communities, generally on a slight 

 elevation in grassy swamps or marshes. The nest is 

 made up of weeds or grasses and the eggs, usually three, 

 are very variable — from whitish or buffy to olive-brown, 

 heavily marked with chocolate. They measure 1"80 x 

 1*30. They are roving birds having a harsh, grating 

 cry, to which they give vent especially when they are 

 disturbed on their nests. 



