22 LONGIPENNES: Long-winged Swimmers 



ROYAL TERN 



(65. Sterna maxima) 19 in. 



Adult: Mantle pearly; wing-tip dark gray or frosty black, not 

 conspicuous in flight; dark area much less than in the Caspian; 

 black cap considerably elongated behind, largely white in winter; 

 bill orange-red, relatively small. 



Immatures have tip of wings and tail dark gray. 



Slightly smaller than the Caspian species, which, at a dis- 

 tance, it closely resembles. At short range, however, the 

 smaller bill is quite distinctive. 



FORSTER TERN 



(69. Sterna forsteri) 13-16 in. 



Adult, in spring: Mantle pearly; under parts white, some- 

 times pale gray; cap shining black; outer tail-feathers greatly 

 elongated; bill orange; outer web of outer tail-feather white; 

 inner web dark rarely discernible in the field. (Compare 

 Common Tern). 



Adult, in winter: Cap mostly white; nape and area about eye 

 blackish; bill duller; outer tail-feathers much shorter. 



Immature: Mantle washed with grayish or brownish; other- 

 wise like winter adult. 



COMMON TERN 



(70. Sterna hirundo) 12-14 in. 



Adult, in spring: Light gray below; bill dark red, black-tipped; 

 outer tail-feathers long and slender, dusky on outside web, in- 

 side web white (compare with Forster). 



Winter adults and immatures closely resemble the Forster 

 except for smaller size. 



These two species are not easily distinguished in the field, 

 especially in winter dress. Note relative size, bill colors, and gray 

 breast of the Common in spring. 



