AN ESSAY ON BIRD-MIND 121 



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

 up the ceremonies of courtship j 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 between 

 the cerebral centres concerned with nest-building and 

 with sexual emotion in general. Thus we almost 

 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 con- 

 struction 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 display 

 before the hens ; and the Peewit plucks frenziedly 

 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 before 

 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 



