GULLS) AND) TRERINS. 39 
Owing to the great diversity of its haunts the 
Black-headed Gull is almost omnivorous in its diet. 
Inland it feeds on grubs—especially wire-worms— 
insects, worms, fresh-water fish, and newly sown 
grain, as I have often ascertained by dissection ; on 
the sea coast it subsists on fish, crustaceans, and 
various odds and ends obtained about harbours or 
vessels. It seeks its food both whilst swimming 
about the water, fluttering above it, or when 
walking on the shore. This Gull is much more 
Tern-like in its habits than the larger species we 
have already dealt with. Of its services to the 
agriculturist there can be no question ; it is just as 
useful on the land as the Rook, without that bird’s 
few little pilfering ways. 
The Black-headed Gull is an inland breeding 
species, and resorts to marshes, wet moors, and 
meres, at varying distances from the sea. Some- 
times these breeding-places are in fairly well- 
timbered districts, and often surrounded by trees 
and bushes. This Gull, too, is remarkably 
gregarious during the breeding season, and some 
of its colonies are very extensive, consisting of 
‘many thousands of pairs. The “gulleries” are 
visited for nesting purposes in March or April, and 
as the birds return to the same spots year after 
year, they probably pair for life. Nesting begins 
in April. Most of the nests are made upon the 
ground in rush tufts, in hassocks of coarse grass 
and sedge, amongst reeds in shallow water, on 
