140 ANNALS OF SCOTTISH NATURAL HISTORY 



In the spring, when the fields are being ploughed, worms 

 constitute a large proportion of its diet, together with various 

 grubs, etc., which the operation serves to unearth. 



Later, when grain is being sown, some, at least, take to a 

 graminivorous diet. On several occasions, at this period, I 

 have examined specimens that have been shot, and found 

 every one to contain more or less corn in their crops. 



Flying insects constitute a considerable portion of its 

 food during summer. Many times I have seen them gorged 

 with crane flies which had just emerged from the pupa stage 

 in haugh-land or fields of coarse grass. The good they do in 

 this respect is very great. A large number of moths are 

 also taken. The gulls may be seen for hours in the evening 

 hawking over the fields, and they are quite expert at capturing 

 even the swiftest flying insects. It is capable of exerting 

 considerable wing power. Several years ago I was much 

 interested in watching it feeding on the caterpillar of a 

 moth which was exceedingly numerous on the birch trees 

 along the shores of Loch Shin in Sutherlandshire. The gulls 

 kept flying round and round the trees, and were continually 

 picking the caterpillars from the twigs or from the threads 

 by which many were hanging suspended in mid-air. Their 

 evolutions while so engaged were exceedingly interesting and 

 graceful, and in a manner suggested the flight of the nightjar. 



During a " rise " of Ephemeridae on a river or stream 

 the Gulls levy a considerable toll on the insects, and where 

 they are numerous and the hatch of fly small, not many of 

 the latter escape. On the Tay I have seen more than a 

 hundred Gulls, common and black-headed, all busily engaged 

 during a rise of duns and yellow-sallies, and also at other 

 places have witnessed numbers taking May flies and March 

 Browns. Anglers have a distinct grievance against them 

 in this respect. 



The injury in this way to fishing, however, is not so 

 serious as in the actual destruction of the fish themselves. 

 On a certain stream in the south of Scotland, which contains 

 quantities of parr and small trout, numbers of Gulls may be 

 seen any day during the spring and summer industriously 

 hawking up and down, backwards and forwards, over the 

 shallows, and ever and anon making a dash at a fish. If the 



