85 



8g8. ? Sex ; Cheshire; December, 1903. — Filled with grass 

 and a few fragments of dung-feeding beetles (Aphodius spp.). 



899. ? Sex ; near Chester ; 3rd December, 1904. — Remains of 

 about 20 earthworms ; a few blades of grass ; 6 small pebbles. 



Summary of stomach contents. — 2 contained insects of the 

 indifferent group ; 1, crustaceans ; 1, worms ; 2, grass. 



Summary of 80 Pellets. — 36 contained insects of the injurious 

 group ; 1, beneficial group ; 38, indifferent group. 



Field Notes. — This Gull, more than any other, is often found 

 inland at some distance from the sea, and it may frequently 

 be seen associated with Rooks either following the plough or 

 searching for food on cultivated land and pastures ; moreover, 

 the " gulleries " of this species are frequently at considerable 

 distance from the coast, so that it is much more dependent 

 upon the inland fauna for its food than any of its congeners ; 

 hence we find that its dietary consists of some of the com- 

 moner insects which are met with in its inland haunts. 

 These are often captured during flight. 



900. Destruction of Crane Flies. — Attention has already been 

 given* to the enormous number of " leather jackets" which 

 devastated the pasture-lands of the Dee Marshes in 1901. 

 When the Crane Flies (Tipula oleracea) appeared these 

 were attacked by flocks of Black-headed Gulls, " and to such an 

 extent did they wage war against these insects that their 

 ' pellets ' or ' castings ' were left scattered over the land in 

 hundreds, looking like little bundles of tightly-packed dead 

 grass. On soaking one of the ' pellets ' in water it was found 

 to contain the remains of about 400 Crane Flies and 1,600 of 

 their eggs ; the latter had evidently been taken while yet in 

 the body of the parent. Each pellet probably represented a 

 single meal, and there can be but little doubt that each bird 



. would make at least ten meals daily of these insects. If this 

 were so a single Gull would be accountable for the enormous 

 number of 4,000 Crane Flies and their eggs per day, making 

 an aggregate of 28,000 per week. As the Gulls flocked together 

 in hundreds the number of insects which they devoured may 

 better be imagined than described.' ' Fortunately the birds 

 were and are still strictly protected in this area. 



* See Rook, p. 54. 



