36 BRITISH SEA (BIRDS. 
cliff, against which the waves are for ever beating 
in ceaseless strife. Except during the three months 
or so of the breeding season, this Gull is seldom 
seen at its nesting sites. In April or May the birds 
collect at their various stations, never quite to leave 
them again until the young are able to fly. Itisa 
very gregarious bird, and some of these “ gulleries ” 
are very extensive, containing many thousands of 
pairs. In some localities, however, where the ac- 
commodation is either limited or unsuitable, but a 
few birds congregate to form a colony. The nests, 
often made as close together as they can be wedged, 
are built upon the ledges, shelves, and prominences 
of the rocks. Favourite spots are where the cliffs 
overhang, or at the entrance of a cave or hollow in 
the precipice. They are made at varying heights 
on the cliff, tier above tier, the lowest often within a 
few feet of high-water mark, but the most crowded 
places are usually about midway up from the sea. 
The nests are large and well made, many of them 
apparently the accumulation of years, composed 
externally of turf and roots, with much of the soil 
attached, and caked together. Upon this foundation 
a further nest of sea-weed and the stalks of various 
plants is formed, finally lined with finer and dry 
grass, and sometimes a few feathers. The nests 
and the cliffs in their vicinity are thickly white- 
washed with the droppings of the birds. The 
eggs are two or three in number, rarely four, 
and vary from greenish-blue, through pale buff 
