ii6 A HISTORY OF BIRDS 



The keenness of the struggle for existence between differ- 

 ent organisms occupying the same area is, and can only be, 

 appreciated by us in part ; we get but occasional glimpses of 

 what is going on in this direction. And thus it seems as though 

 the conflict between birds and their animal neighbours is con- 

 fined mainly to the brooding parents and their offspring. 

 During the breeding season birds are subjected to a very heavy 

 toll. Snakes and lizards and rats devour their eggs. Squirrels 

 and prowling carnivores destroy their young, while the sitting 

 bird is always in danger of beir^g surprised and seized when 

 brooding, though the mortality from this last source is trifling 

 compared with that which overtakes the eggs and young. 

 When the critical period of reproduction is passed in the 

 neighbourhood of human communities, the destruction, especially 

 with regard to eggs, is appalling, and it appears to attain its 

 highest intensity where civilisation is most advanced. This is 

 largely due to the ravages made for economic purposes. 



The young birds, from the moment they leave the egg till 

 the time they have learned to fly, run the gauntlet of a host of 

 enemies, even invertebrates taking part in the carnage. For 

 Dr. Alcock has recorded in his charming book, A Naturalist 

 in Indian Seas, how when landing on Pitti Island, in the 

 Laccadive Sea, he found "every foot of the ground above 

 high water-mark literally carpeted with young Terns of two 

 species, many living and nearly full-fledged, many dead and 

 rotting, and many reduced to clean-picked skeletons with only 

 the quill feathers still sticking to the wing-bones. . . . We soon 

 discovered that one great cause of the wholesale destruction of 

 young birds was the voracity of swarms of large hermit crabs 

 {CcBnobita), for again and again we found recently killed birds in 

 all the beauty of their first speckled plumage being torn to 

 pieces by a writhing pack of these ghostly crustaceans. There 

 were plenty of large ocypode crabs too {O. ceratophthalmus) 

 aiding in the carnage." And he continues : " Moseley, in his 

 Notes of a Naturalist on the Challenger, made mention of a 

 grapsus crab that he saw on St. Paul's Rocks carrying off a 

 newly hatched Tern, but such an accident does not shock one's 

 feelings nearly so much as does the thought of full-grown young 

 birds, nearly ready to fly out into the world and to exercise 

 their intelligence, being overpowered by force of numbers 



