248 SPOLIA ZEYLANICA. 
throughout temperate Europe, all Africa, and Southern Asia 
to Australia. Many birds are migrants in the southern part 
of their range, but some are resident. 
Habits —Found more in marshes, paddy fields, and round 
tanks’ or lagoons than by the open coast. Like gulls in 
England they often follow the plough. Many of our birds are 
migrants, seen only during the north-east monsoon. Some 
birds stay, chiefly immature individuals in winter dress, but 
others are in full summer plumage, so that the nest and eggs 
may yet be found in Ceylon. 
The birds breed in colonies on beds of water-lilies or other 
floating plants in large swamps; the nest is a fairly large 
structure of reeds or straw. The eggs are generally three, 
pale olive or greenish, with blotches of purple-gray and brown. 
Average size about 1°50 by 1-10. 
HYDROCHELIDON LEUCOPTERA (Blanford, Vol. IV., p. 308 ; 
Legge, p. 1000). 
The White-winged Black Tern. 
Description —In winter plumage closely resembles the 
previous species, but is slightly smaller; the bill is smaller 
and darker, and on examination of the series in the British 
Museum the forepart of the head appears to be whiter, the 
black spots of the crown seldom coming further forward than 
the eye. In summer the species is at once recognizable, 
as the head and neck, the back, and the under parts as 
far as the vent, together with the wing lining, are black. 
The coverts on the edge of the wing are white, as are the 
rump and the upper and lower tail coverts ; tertiaries dark 
gray ; remainder of wing lighter gray, except for the first few 
primaries, which are often sooty-brown, where the frosting has 
worn off. 
Young birds are mottled with dark brown on the crown and 
mantle, and have whitish upper tail coverts. 
Bill livid red in summer ; blackish-red in winter ; iris d&rk 
brown ; legs vermilion. 
Length 9:5; wing 8°25; tail 2°8; tarsus +75; bill from 
gape 1:3. 

