DIRECTORY TO BIRDS OF EASTERN NORTH AMERICA. 51 



2. CABOT'S TERN, A. ACUFLAVIDA. Smaller than 

 1 (14.00) and more slender; bill, more slender, black, yellow 

 at tip, Fig. 61. Fig. 61. 



Flight, easy and 



graceful. Cries, - ^4^||B% y x . 



harsh. Breeds com- ^' 



monly on the Ba- ^ 

 hamas and Gulf 

 Coasts in May and 

 June, wandering 

 northward in late 

 summer, casually 

 as far as Chatham, 

 Mass. Winters on 

 the Florida Keys. F, C, C, 2. 1-7. 



d. Pale-backed Terns. Sterna. 

 Size, rather small ; mantle, pearly-blue ;black cap present 

 in adults in sum- Fig. 62. 



mer in all of our 

 species excepting 

 1 ; bill, very slen- 

 der and sharply 



pointed, plates F,C,d, 2. 



3 and 5 ; tail, deeply forked with outer feathers narrowed 

 terminally, figs. 62, 64; graceful, swiftly flying birds popu- 

 larly known as Sea Swallows. 



1. TRUDEAU'S TER]S,S. TRTJDEAUI. About the size of 

 2; form similar; head, white, dusky spot on either side ex- 

 tending from bill to ear coverts and enclosing eye; under 

 tail coverts, white ; outer primaries, silvery-white ; remain- 

 der of plumage, pearl gray ; bill, black, yellow at base and 

 tip. In winter, entire lower parts, white. Southern S. A. ; 

 accidental in N. J. and Long Island (Audubon). 



2. COMMON TERN, S. HIRUNDO. 14.00; mantle, rath- 

 er dark ; outer tail feather not extending beyond tip of the 



