LEAST TERN 317 



with black and white. Even in the autumn plumage it 

 may be readily distinguished from any other tern, except 

 the Least, by its small size. Its tail, too, is less deeply 

 forked than in other adult terns. From the adult Least 

 Tern it may be distinguished by the dark gray of its upper 

 parts and by its black bill. An immature Least Tern has 

 a blackish bill, but is considerably smaller than a Black 

 Tern, and has a brownish tinge on its upper parts. 



Least Tern. Sterna antillarum 



9.00 



Ad. in summer. — Forehead ivhite, inclosed by black lines from 

 the eye to the bill ; rest of top of head black ; back, wings, and 

 tail light pearl-gray ; under parts white ; bill bright yellow, tip 

 blackish. Ad. in autumn. — Similar, but head grayish-white; 

 bill dull yellowish. Im. — Like fall adult, but back spotted with 

 brownish ; bill blackish. 



The Least Tern is a summer resident of southern New 

 England and Long Island from May to September; it is 

 local, and nowhere common. It breeds sparingly on the 

 south shore of Martha's Vineyard, and perhaps at Chatham 

 on Cape Cod. Its cry has been described as a " shrill 

 staccato yip, yip, yip " (Job). Its size distinguishes it 

 from the Common Tern. The light pearl-gray of its back 

 and wings distinguishes it from the occasional Sooty Tern 

 that might occur on the same coast in August or September. 

 The ivhite border that separates the black cap from the 

 bill is an excellent field-mark, but this must not be con- 

 fused with the whitish forehead of the immature Common 

 and Roseate Terns. 



Roseate Tern. Sterna dongalli 



15.50 



Ad. in summer. — Top of head black ; wings and back pale 

 pearl-gray ; tail white, the outer feathers much longer than the 



