426 VERTEBRATE FAUNA OF LAKELAND 



stages of putrefaction. In 1891 an alarming death-rate prevailed 

 among the old birds at Moorthwaite ; — the colony was almost 

 decimated, and was reduced from being the leading colony in our 

 midst to a second-rate position. That the birds died from want 

 of food is impossible, because they were nesting at a time when, 

 owing to the lateness of the spring, the country round was being 

 extensively ploughed. Those that I examined were in fine 

 plumage, but had wasted away, as though exhausted by some 

 kind of fever, the germ of which had found favourable condi- 

 tions for incubation, owing to the resident population of Gulls 

 being grossly overcrowded. There can be no doubt that the 

 too rapid increase of this bird is amply secured by those natural 

 conditions which, in every season, kill off a certain number of 

 the young which would otherwise be raised. But in dry sum- 

 mers many young birds die from want of worms and grubs, which 

 form the chief food of the nestlings even on the coast-line. 



In summer the old birds themselves feed largely on moths 

 and other winged insects, as noted long ago by Nicolson and 

 Burn, who wrote of Betham, near Witherslack: 'Within this 

 manor also is Helflach Tower, now in ruins. Helflack mosses are 

 remarkable for the ant or pismire. About the middle of 

 August, when they take wing, a thousand sea-mews may be 

 seen here catching these insects. The neighbours call them the 

 pismire fleet.' 1 At other times they feed on small shells, such 

 as they find readily on the sands. I have found numerous 

 pellets, entirely composed of small mussels, which these birds 

 had bolted entire and afterwards rejected. An intelligent 

 farmer who watches over the Moorthwaite colony pointed out 

 to me that the birds appear there to feed on grass ; at any rate, 

 they crojj the grass on the banks of the lough. He values them 

 highly as destroying enormous quantities of injurious insects, 

 but finds that though they do not care for fresh-sown wheat or 

 barley, they will feed on oats with such avidity that he has 

 often had to sow furrows twice over. ' They shell the oats 

 before bolting the kernel.' But they are so far from being 

 dainty feeders that they regularly frequent localities in which 

 they can obtain the offal discharged from bone-mills, or even 

 1 Hi-story of Cumberland and Westmorland, vol. i. p. 225. 



