Some Habits and Instincts of Young Birds. 35 



instinctive response to a specialized auditory stimulus 

 was completely lost at the end of ten or twelve days. 



The results of my own observations may now be briefly 

 described. I took two chicks ten days old to the yard 

 whence I had received the eggs from which they had been 

 hatched, and opened the basket wherein they had been 

 conveyed, about two yards from a hen which was clucking 

 to her brood. Though they were not in a frightened con- 

 dition, as shown by the fact that they jumped on my hand 

 and ate grain off it, scratching at my palm, they took 

 no notice whatever of the clucking of the hen. I then 

 placed them with another hen in a small fowl-house ; but 

 they took little heed of her, neither running to her nor 

 seeming frightened, or, if at all, but little. Three other 

 chicks were taken when they were thirteen days old to the 

 yard, and were put down outside a fowl-house in which 

 a hen was clucking to her brood. They also took no 

 notice of the sound, but scratched about quite uncon- 

 cernedly. Subsequently they were placed with the hen, 

 who seemed inclined at first to drive them away, but 

 afterwards looked more kindly on them, though they did 

 not keep close to her like the others. I went over on the 

 following day, and when I bent down and held out my 

 hand, one of my little friends ran to it and nestled down 

 confidingly. So far my observations confirm what Spal- 

 ding says concerning the loss of the instinctive response, 

 or, at any rate, its absence after the lapse of a few 

 days. But] the following case shows that the instinc- 

 tive recognition of the hen, if indeed it exist at all, is 

 very soon lost. I took a chick at two and a half days 

 old (that is to say, at about the same age as Spalding's 

 birds) to its own mother, which had three chicks. These 

 followed her about, and ran at once to her when she 

 clucked and pecked on the ground. The little stranger 



