202 The Passenger Pigeon 



nests and egg, at times by the female, more often by- 

 others of the flock, and the killing of the young birds', 

 after they leave the nest, by the old males, explains in 

 part the slow increase in the flock. 



When the pigeons show signs of nesting, small twigs 

 are thrown onto the bottom of the inclosure; and, on 

 the day of our visit, I was so fortunate as to watch the 

 operations of nest building. There were three pairs 

 actively engaged. The females remained on the shelf, 

 and, at a given signal which they only uttered for this 

 purpose, the males would select a twig or straw, and in 

 one instance a feather, and fly up to the nest, drop it and 

 return to the ground while the females placed the 

 building material in position and then called for more. 



In all of Mr. Whittaker's experience with this flock 

 he has never known of more than one egg being 

 deposited. Audubon, in his article on the Passenger 

 Pigeon, says: "A curious change of habits has taken 

 place in England in those pigeons which I presented to 

 the Earl of Kirby in 1830, that nobleman having as- 

 sured me that, ever since they began breeding in his 

 aviaries, they have laid only one egg." The eggs are 

 usually laid from the middle of February to the middle 

 of September, some females laying as many as seven or 

 eight during the season, though three or four is the 

 average. 



The period of incubation is fourteen days, almost to 

 a day, and, if the egg is not hatched in that time, the 



