220 Order XIV 



the water, but they skim along over the tops of the 

 waves, darting down to secure a fish and not uncom- 

 monly submerging themselves by the violence of their 

 sudden plunge. Sand-eels and the like from shores 

 left dry by the tide form part of their diet, but those 

 Terns and Gulls that breed inland have a much more 

 varied bill of fare. Gulls, indeed, are practically 

 omnivorous, for, in addition to the creatures of the sea, 

 they feed on worms, grubs, grain, and even berries, 

 not to mention the young birds and lambs destroyed 

 by such bold robbers as the Greater Black-backed Gull. 

 It is a pretty sight to see flocks of Gulls usually of 

 the Black-headed or Common species following the 

 plough ; they keep close behind the ploughman, rising 

 in a cloud from time to time for no obvious reason and 

 settling down again immediately to resume their inter- 

 rupted repast. In many towns, Perth being a striking 

 instance, they sit on the roof -ridges in the early morning 

 waiting for any refuse that may be thrown out ; later 

 in the day they are equally on the alert as scavengers 

 of the quiet streets. In Perth the Black-headed Gull, 

 which breeds close at hand, is the bird in question, 

 but in other towns near the sea the Common Gulls, or 

 less often the larger species, crowd upon the tops of the 

 suburban "dust-heaps" and fight with each other for 

 the delicacies they find there. Gulls do not scream like 

 Terns, but utter querulous or mewing cries, which in 

 the case of the largest species become harsh croaking 

 sounds. Both are distinctly gregarious on the coast, 

 as well as at their nesting-colonies, and there is little 

 difference in this respect; perhaps Terns congregate 

 more closely when sitting on the shore, Gulls when on 

 the cliffs or inland marshes. But all the inland species 



