380 THE ZOOLOGIST. 



and cultivation, by still further favouring the earthworm, only 

 confirmed the process. 



Summing up the essential conditions of the breeding habitat, 

 we have : a sheet or stream of water ; a nesting area to which 

 the eggs, and more especially the young, have a protective 

 resemblance ; a general feeding-ground accessible for the adults 

 and providing a large supply of earthworms ; comparative 

 immunity from enemies in the breeding territory. A local 

 feeding-ground is of so general occurrence, that it may be 

 regarded as approaching the essential. The requirements here 

 are accessibility for the young, a large stock of tipulid and 

 coleopterous larvae, and a certain freedom from disturbance. 



In summer enemies have a greater influence than in winter. 

 Most injury is wrought before the end of incubation. So much 

 is this the case that, if only the young can be hatched, they 

 have a very good chance of reaching the stage of flight. Most 

 destruction is caused by man. He takes the eggs, while youths, 

 as I have observed, stone the young. The adult birds do 

 not suffer in themselves through the agency of man. On the 

 contrary, they benefit, as I have shown. In nesting areas, to 

 which sheep and cattle have access, the eggs may be trodden 

 upon. On one occasion I witnessed the actual event : on 

 another I found a nest containing crushed and flattened eggs, 

 to account for whose state cattle were the most likely explana- 

 tion. The young do not appear to suffer from these animals. 

 But they may come to grief from the chance step of a human 

 being, as then the adult birds do not interrupt the special 

 means which serve as stimuli for the crouching reaction. 

 Without disturbing the crouching response in the least degree, 

 I have abraded the skin of a chick which I failed to see in time 

 to avoid the accident. The Buzzard causes a good deal of 

 commotion, but has not been seen to attack the young. The 

 Sparrowhawk, Kestrel, and Merlin produce little effect. The 

 Lesser Black-backed Gull, as it sails over the breeding area, has 

 a profound influence upon the situation. The young Oyster- 

 catchers crouch at once in response to the warning call of the 

 adults, which, thereafter, stand absolutely still in dumb watchful- 

 ness. No attack has been observed. The Black-headed Gull, 

 which often tries to snatch away the young of the Binged Plover 



