2QO THE NESTS AND EGGS OF BRITISH BIRDS. 



circumstances, its breeding area is wide and varied, not 

 confined to one or two chosen localities, as is the case 

 with so many other species. Early in spring the birds 

 return to their nesting-places, but the breeding season 

 does not commence before May. The nests are built 

 in a great variety of situations. In some cases they are 

 made on ledges and in crevices of the cliffs, or amongst 

 crags or in sheltered hollows of the grassy downs ; in 

 others they are built on the summit of rock-stacks, or 

 amongst the dense growth of sea-campion and thrift, as 

 at the Fame Islands. When on the cliffs the nest is 

 usually larger than when on the ground or amongst 

 crags. It is composed of turf, dry sea-weed, straws, and 

 stalks of marine plants, and lined with grass, much of it 

 often semi-green. Sometimes the entire nest is merely 

 composed of a few straws and bits of dry grass. I have 

 half a dozen, taken from near Berry Head, that could all 

 be grasped in one hand. When the breeding-place is in- 

 vaded the birds become very clamorous, and fly to and 

 fro in alarm, rising from their nests and settling again 

 at the first opportunity. When the nests are on cliffs 

 the birds usually leave them with reluctance. 



RANGE OF EGG COLOURATION AND MEASUREMENT : 

 The eggs of the Herring Gull are two or three in 

 number. They vary in ground colour from pale bluish- 

 green to olive-brown and yellowish-brown, somewhat 

 sparingly spotted with dark brown, and with underlying 

 markings of paler brown and gray. The markings are 

 usually in the form of spots rather than blotches, but 

 on some eggs they take the latter character. Average 

 measurement, 2*9 inches in length, by 2'O inches in 

 breadth. Incubation, performed by both sexes, lasts 

 twenty-six days. 



DIAGNOSTIC CHARACTERS : As a rule the eggs of 

 this Gull may be distinguished by their size and the 



