340 BIEDS OF BRITISH GUIANA. 



where her home had been. She almost upset herself in vain 

 efforts to alight on the nest, where the nest was not. Only after 

 crouching for a full minute among the few straws that were left, 

 did she realize that it was gone. She rushed to the edge of the 

 beam, looked around and then back to where the nest ought to 

 be, dragging the straws about -as if the nest might be hidden 

 beneath them ; then to the edge to look at the ground below, and 

 then back. She repeated all these movements several times, and, 

 at last, thinking, that some terrible mistake had been made, flew 

 about for a few minutes before returning to repeat her former 

 operations. Again she returned, this time with her mate, who in 

 turn, showed excitement, and to whom the mystery was as inex- 

 plicable as to her. Finally they perched together on the beam 

 edge. Their eyes searched in all directions, though chiefly 

 downward, as if the nest had fallen and rolled to some obscure 

 hiding place. Then they flew away only to return again and 

 again, hoping each time to find the nest in its old position. 'J'he 

 nest remained in plain sight, but, though they often passed close 

 hj, the idea never occurred to them to investigate it. 



"At last, deciding that it was not bn the ground and not 

 thinking to search elsewhere, they went to roost on the original 

 site. Doubtless it was instinct that caused them to search below, . 

 but it must have been the habit of finding the nest in the same 

 place day after day, which prompted them to seek only in the one 

 spot above, although the nest stood in plain view before them. 



"Instinct and actual habit are so closely associated that at 

 times it is scarcely possible to distinguish between them. What 

 often is taken for instinct really is a newly acquired habit which, 

 under other conditions, might be altered. Thus it happened, on 

 the following day, that the Martins instinctively commenced to 

 build a new nest, but, from habit, used the old site. From habit 

 they roosted there, even though they knew some enemy to be 

 about that had the knowledge of their hiding place, and though 

 an innate instinct must have urged them to choose another 

 location. 



" I do not pretend to intimate that newly formed habit runs 

 contrary to instinct among all birds and animals, for such is not 

 the case. If it were, there would soon be no animals or birds 

 left, nor other intelligent life. If the weak inoffensive bird in the 

 bush did not instinctively change its abode after that abode had 



