FAM. LX. TERNS AND GULLS 321 



FAMILY LX. TERNS AND GULLS (LARID^E) 



A large family (100 species) of birds, divided about equally 

 between the two subfamilies. 



The Terns are noisy, shrill-voiced, nearly white, swallow-like 

 birds, generally much smaller than the gulls. They have, usu- 

 ally, notched or forked tails, while those of the gulls are even. 

 The terns are almost entirely confined to the coasts ; they 

 are most abundant on islands and are numerous on the shores 

 of fresh-water lakes. The gulls are less common except near 

 salt water, and are generally found out at sea far from shore. 

 Terns are readily distinguished from other birds when in the 

 air, but it is almost impossible to determine the species with- 

 out having them in hand. Terns can easily be separated from 

 gulls by the position of the head while flying. Gulls hold 

 their heads in line with the body, while terns hold theirs 

 pointing downwards. 



Gulls are hoarse-voiced, large, long-winged, sea and shore 

 birds, usually with square tails. They are good swimmers, 

 spending much of their time on the water. In this they differ 

 from the terns, which are much of the time on the wing. 

 Gulls procure their food by gathering it from the surface 

 of the water with their strongly hooked bills. Terns plunge 

 downward into the water from the air, often disappearing 

 beneath the surface. Gulls have a varied diet, — mammals, 

 birds, eggs, and fish. Terns live mainly on fish, though some 

 eat insects. The nests of both gulls and terns are almost 

 always on the ground. 



Key to the Subfamilies 



* Bill more or less hooked, the culmen much curved near tip ; i tail about 

 square (No. 25 has a forked tail with the outer feathers rounded at 

 tip, white under parts, and wing over 10 long) ; colors 

 generally white with a darker, usually grayish mantle on * 

 the back (young birds have much mottled browns and 



white) Gulls, p. 328. 



apgar's birds. — 21 



