AN ESSAY ON BIRD-MIND 123 



those of nest-building, are taken and used to build 

 up the ceremonies of courtship; but whereas in the 

 former case the actions are simply those which are 

 most natural to and best performed by the bird, in 

 the latter there is, no doubt, actual association be- 

 tween the cerebral centres concerned with nest-build- 

 ing and with sexual emotion in general. Thus we al- 

 most invariably find the seizing of nest-material in the 

 beak as a part of courtship, and this is often extended 

 to a presentation of the material to the mate. This 

 we see in the Grebes, with the dank weeds of which 

 their sodden nest is built; the Divers use moss in the 

 construction of theirs, and the mated birds repair to 

 moss banks, where they nervously pluck the moss, 

 only to drop it again or throw it over their shoulder. 

 Among the Warblers, the males pluck or pick up a 

 leaf or twig, and with this in their beak hop and dis- 

 play before the hens; and the Peewit plucks fren- 

 ziedly at grass and straws. The Adelie Penguins, so 

 well described by Dr. Levick, make their nests of 

 stones, and use stones in their courtship. 



A curious, unnatural transference of object may 

 sometimes be seen in these Penguins. The normal 

 course of things is for this brave but comic creature, 

 having picked up a stone in its beak, to come up be- 

 fore another of opposite sex, and, with stiff bow and 

 absurdly outstretched flippers, to deposit it at the 

 other's feet. When, however, there are men near the 

 rookery, the birds will sometimes in all solemnity 

 come up to them with their stone offering and lay 



