CASPIAN TEEN 381 



primaries, frosted with a similar colour which, when worn, 

 shows a darker ground-shade ; breast and abdomen, white. 



Adult female nuptial. Similar to the male plumage. 



Adult winter, male and female. Head, white, with 

 brownish-grey streaks, which form patches on either side of 

 the eye and over the ear. 



Immature, male and female. Head streaked with 

 greyish-black ; back, scapulars, and wings, mottled and 

 striped with brown and tinged with light yellowish-buff. 



BEAK. Black ; strong and thick. 



FEET. Black, tinged with red; webs moderately in- 

 dented. 



IRIDES. Dark brown. 



AVERAGE MEASUREMENTS. 



TOTAL LENGTH ... 15 in. Female slightly smaller. 



WING 12-5 



BEAK 1-9 ,, 



TARSO-METATARSTJS 1*5 ,, 

 EGG 2 x 1'4 in. 



Allied Species and Representative Forms. S. macrotarsa, 

 larger in size and with lighter coloured plumage, breeds in 

 Australia. 



CASPIAN TERN. Sterna caspia (Pallas). 



Coloured Figures. Gould, 'Birds of Great Britain,' vol. v, pi. 

 68 ; Dresser, ' Birds of Europe,' vol. viii, pi. 584 ; Lilford, 

 ' Coloured Figures,' vol. vi, pi. 5. 



It is rather remarkable how irregular the visits of this 

 species of Tern are to our coasts, for, as pointed out by 

 Professor Newton, 1 it is a bird of wide distribution ; more- 

 over, some of its breeding-stations are at no great distance 

 from the British Isles. As in the case of other rare Terns, 

 it has been taken most frequently in the maritime counties 

 of the east and south of England. 



1 ' Dictionary of Birds,' p. 957. 



