CASPIAN TERN 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 
ereyish-black; back, scapulars, and wings, mottled and 
striped with brown and tinged with light yellowish-buff. 
Beak. Black; strong and thick. 
Freer. Black, tinged with red; webs moderately in- 
dented. 
Ir1mpEs. Dark brown. 
AVERAGE MEASUREMENTS. 
ToraL LENGTH ... 15 in. Female slightly smaller. 
WING ae per a5 eee 
BEAK aes epg OP 
TARSO-METATARSUS'7 1°5,, 
Hae i aba once Mee ims 
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, pl. 
68; Dresser, ‘ Birds of Europe,’ vol. viii, pl. 584; Lilford, 
‘Coloured Figures,’ vol. vi, pl. 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,! 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. 
! ¢Dictionary of Birds,’ p. 957. 
MY Is 
