TEKNS. Ill 



Pale=backed Terns. 



Smaller Terns; tails deeply forked; out- 

 er feathers narrowed terminally, fig. 81. All 

 of our species, excepting 79, have black caps 

 and pale blue-gray mantles. Flight, graceful 

 and rapid. 



78. TRADEAU TERN. 

 Size of Common Tern, but differs from 

 this and all others of the group in having 

 head white with dusky spot on either side 

 extending from bill to ear coverts enclosing 

 eye; remaining plumage, pearl-gray; bill; 

 black, yellow at base and tip; in winter en- 

 tire under parts white. Southern S. A., acci- 

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



79. COMMON TERN. 

 Size, 14; mantle, rather dark; tips of out- 

 er tail feathers not extending beyond points 

 of folded wings and their outer webs are dus- 

 ky, fig. 81; chiefly white below; bill, red 

 black at tip, fig. 80; in winter, cap white 

 black on occiput only. Young with forearm 



