BLACK-HEADED GULL. 253 



various parts of the island, l)ut owing to disturbance, 

 none of these became permanent until within recent 

 years ; now, however, on several parts of the south end, 

 there are small communities formed, and these are said 

 to be increasing. An old-established, but not extensive, 

 Gullery on a floating island on a small tarn upon the 

 Bleasdale fells, exhausts the Lancashire list, and this 

 appears to be becoming deserted, the birds in the present 

 year (1884) not having returned up to the beginning of 

 May. The few eggs which the late Mr. H. Durnford 

 {ZooL, 1873) found near Formby in 1873 do not appear 

 to have resulted in the establishment of a permanent 

 settlement. Large flocks of Black-headed Gulls follow 

 the plough, and feed on the larvae turned up by it, thus 

 doing valuable service to the farmer, and the late Eev. 

 J. D. Banister wrote {ZooL, 1844, p. 577) that in the 

 twilight they also feed largely on the night-flying moths, 

 he having repeatedly shot birds at a late hour, with 

 their pouches crammed with them. The same gentle- 

 man has some interesting remarks (ZooL, 1845, p. 881) 

 on the change of the herbage on Pilling Moss due to 

 the presence of the Gulls. He says " originally on this 

 moss the common Wild Duck, Teal, Snipe, Curlew, 

 Golden Plover, Dunlin, and even Pied Grouse, bred 

 extensively. A few pairs still occupy certain districts, 

 where they annually breed. The Black-backed and 

 Black-headed Gulls have within the last twelve years 

 succeeded the ancient colonists. The poor heath, in 

 the vicinity of their breeding-place, has been almost 

 annihilated by their excrement, and in its place has 

 sprung up a rich and varied vegetation. No one who 

 formerly knew this moss, and has witnessed the recent 

 remarkal)le change, doubts for a moment that it has 

 been entirely effected by the dung of these birds, 



