440 STERNID^ STERNA 



nearly white, outer webs of the outer feathers very pale grey, so 

 that there is little contrast in shade between the two webs ; below 

 grey. Bill and feet cherry-red. 



Length about 16 ; wing 10-5 ; tail 7'5 to 8-0 ; depth of fork 4-5 

 to 5-0; culmen 1-45; tarsus -7. 



In the non-breeding dress the forehead and crown are mottled- 

 grey and black. Young birds are white below and have the outer 

 webs of the tail-feathers greyer ; the bill and feet vary from dull 

 livid-red to blackish. 



FIG. 139. Head of Sterna vittata in breeding dress, x ji 



Distribution. This Tern is found throughout the southern 

 portion of the Atlantic and Indian Oceans, from the neighbourhood 

 of Ascension and Tristan da Cunha to Kerguelen and St. Paul; 

 there are examples of this species in the South African Museum, 

 recently identified by Mr. Howard Saunders, obtained in Table Bay 

 in August, near Dassen Island in June, in False Bay in July, and 

 in Saldanha Bay in September; all are in non-breeding plumage. 

 Probably this bird is common enough about the coast of South 

 Africa, but has been hitherto confounded with S. fluviatilis and 

 S. macrum, both of which it closely resembles. 





765. Sterna fluviatilis. Common Tern. 



Sterna hirundo, Linn. Syst. Nat. 12th ed. i, p. 227 (1766) [in partj ; 



Beichenoiv, Vog. Afr. i, p. 64 (1900). 

 Sterna fluviatilis, Naum. Isis, 1819, pp. 1847-8; Gurncy, Ibis, 1868, 



p. 263 ; Sharpe and Dresser, B. Eur. viii, p. 263, pi. 580 (1872) ; 



Gurney, in Andersson's B. Damaral. p. 361 (1872) ; Saunders, 



P. Z. S. 1876, p. 649; Sharpe, ed. Layard's B. S. Afr. p. 701 (1884) ; 



