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 primaries are 
less silvery and the tail brownish and deeply emarginate, but less so 
than in the adult. Bill smaller 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 California; 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. 
