Introduction xxi 



in many directions, and we must look for much variation in all 

 minor details. 



The strength of parental instinct, especially in the higher 

 animals, has been recognized from early times, but the subject 

 has not been previously subjected to careful experiment and 

 analysis in birds. 



I have found but few references to even casual experiments. 

 In speaking of the Catbird, Audubon observes that it will sit on 

 its eggs after the nest has been displaced, or even after it has 

 been carried from one bush to another (Ornithological Biography, 

 vol. ii., p. 173). Blackwall, in a later English work (referred to 

 on page 189), gives a good example of the strength which the 

 parental instinct in even a foster-parent sometimes attains. He 

 relates that in August of the year 1825 a neighbor took a young 

 Cuckoo out of a Titlark's nest, carried it home, and put it in a 

 cage, which was hung in a pear-tree in his garden. The foster- 

 parents quickly discovered their nursling, notwithstanding that 

 it had been carried three quarters of a mile from its home, and 

 continued to feed it until it was killed by a cat. 



In another instance, mentioned by Montagu (Ornithological 

 Dictionary, p. 203), a nest of Golden Crested Wrens was moved 

 from its original position, and the old birds were enticed to his 

 study- window, and finally inside the room. The male would 

 never enter, but his mate fed her young in their nest which was 

 placed in a basket on the table at which he sat, and even when 

 he held the nest in his hand, provided he was perfectly motion- 

 less. Such stories no longer occasion surprise, and will receive 

 ample illustration in the pages which follow. 



V 



This study of the activities of birds, which was further 

 undertaken as a relief from the confinement of a laboratory, 

 soon developed from a holiday recreation into most serious work, 

 but the chief difficulty under which I have labored is lack of 

 time. 



The season most valuable to the student of the life and 



