332 BIRDS OF NORFOLK. 



the reed or rotting pieces of" boulder," but when the time 

 of hatching approaches the old birds considerably enlarge 

 the base of the structure, adding dead stems of glad- 

 don till quite a floating raft is formed ; this, as in the 

 case of the great-crested grebe (p. 240), is evidently 

 intended as a resting-place for the young, which other- 

 wise, the nests being only slightly above and quite sur- 

 rounded by the water, would have no dry surface to rest 

 upon. 



It is very rare to observe any signs of immaturity 

 about the breeding gulls. Occasionally one is seen 

 with a barred tail, the last mark of youth, but this is 

 decidedly exceptional ; on the other hand, the birds on 

 the coast are most frequently in immature plumage. 

 The appetite of the black-headed gull seems to recog- 

 nise very little distinction of food ; it has been seen 

 hawking for moths on a summer's evening, flying over 

 the grass like a swallow. Cockchafers, wireworms, 

 aquatic insects, frogs, mice, and even small birds in 

 the nesting-season probably captured on their nests 

 have been known to minister to its necessities. It 

 may be seen miles away, following the plough, doing 

 inestimable service to the farmer, and, strangest food of 

 all, in the year 1863, when great numbers of the young 

 perished from want of food, owing to the long continued 

 drought, Mr. Stevenson tells us "the dead fed the 

 living, since the maggots from the bodies of the dead 

 nestlings formed a scanty provision for those hatched 

 later in the year." 



There is reason to believe that the bulk of the black- 

 headed gulls which breed here pass south in the autumn. 

 Mr. Stevenson says he has frequently distinguished the 

 harsh notes of this species, apparen tly in large numbers, 

 forming part of the flocks of migrants passing over this 

 city on dark autumnal nights, but the place of these 

 wanderers is filled by others, probably arriving from 

 more northerly localities, for this species is one of those 

 most commonly met with on our coast during the whole 

 year, even during the breeding season considerable 

 numbers of immature birds frequent the shore, as it 

 rarely nests till it has assumed its full plumage, which 

 requires two or perhaps three years to acquire. In 



