146 



Forster's and Common Terns occur in coastal waters from Washington 

 southward from late summer to early spring. Their greatest abundance in 

 Pacific coastal waters occurs during spring and fall migrations. From 

 Washington to northern California their occurrence is especially 

 infrequent. 



Arctic Terns, from Washington southwards, are present only during 

 migration periods, late July to early October and May. North of 

 Washington and especially from the Aleutian Islands north, they are 

 present during the summer as well. 



ALEUTIAN TERN (Sterna aleutioa; choices 20 and 20', pg. 64). Since 

 this species occurs rather locally on coastal islands of the Bering Sea 

 and off the Alaska Peninsula, one would have to distinguish it only from 

 Arctic Terns. Besides the characters in the key, the Aleutian Tern's 

 white forehead, black bill and gray back coloration, that is much darker 

 than in the other species, should help in identification. 



Aleutian Terns nest on islands from Norton Sound (Bering Sea) south 

 as far as Kodiak Island and in the eastern Aleutians. They migrate to 

 Asia during non-breeding periods. 



SOOTY TERN (Sterna fusoata; choices 5 and 5', pg. 62). This species' 

 very large size and the black coloration of upper parts set it apart from 

 most other seabirds except perhaps the Black Skimmer; the white in the 

 secondary feathers and large size of the secondaries would be sufficient 

 to identify specimens without heads. A juvenile Sooty Tern is much 

 different from the adult. It is dark brown all over with buffy feather 

 tips, its wings are not as long and pointed and its tail is only slightly 

 forked compared to the adult. 



Sooty Terns could occasionally be encountered near the southernmost 

 coasts of Baja California. Any specimen found should be saved for 

 verification. 



LEAST TERN (Sterna albifrons; choices 16 and 16', pg. 64). Its very 

 small size sets this species apart from other terns. If one found only a 

 wing, without consideration of color, one might consider it to belong to 

 a medium-sized shorebird. 



This species occurs from the spring to fall from San Francisco Bay 

 southwards. 



ROYAL TERN (ste ma maxima; choices 11 and IT, pg. 63) and ELEGANT 

 TERN (s. elegans; choices 14 and 14', pg. 63^. No difficulty should be 

 encountered in distinguishing these from one another or from other tern 

 species. Both occur year round south of northern Baja California. During 

 the fall and winter the Elegant Tern occurs as far north as Humboldt Bay. 

 Royal Tern specimens found north of Point Conception should be saved for 

 verification. 



