84 BEHAVIOR OF PIGEONS. 



but the eggs failed to develop because of probable lack of fertilization. Thus the 

 initial act does not necessarily stimulate and arouse the succeeding activities 

 of nesting and incubation in the male. The female, however, completed the cycle 

 without the cooperation of a mate in nesting and incubation. "I do not under- 

 stand this male. Finding that he used the female white ring (W 1) for his pleasure, 

 but never mated with her properly, so as to take any part in sitting, I gave him 

 another female." (C 7/7.) 



HOMER MALE AND HYBRID FEMALE. 



This pair, consisting of a male homer and a hybrid, was mated on May 29. 

 "They paired, courted, united, built a nest, but never laid or sat." (BB 5.) This 

 phenomenon, according to Dr. Riddle, occurs perhaps more frequently among 

 hybrid females than among non-hybrids. Dr. Whitman cites at least one such 

 case in domestic pigeons, and notes that this failure on the part of the female was 

 a mark of "degeneracy." 



ECTOPISTES. 



In crossing common pigeons with the wild species one finds that the former usually 

 keep up incubation for a few days after their usual time. The wild passenger-pigeon never 

 waits more than 10 or 12 hours. If the egg does not hatch within that time he leaves it; 

 no matter if the shell is broken and the bird nearly ready to hatch, it is deserted. The 

 common pigeons, however, are a little less particular in this respect than are the wild species. 



The egg of a ring-dove mated to a passenger-pigeon developed up to a few days of 

 hatching, but died for some unknown cause. The male passenger was then flying back and 

 forth, calling as he flew. He was evidently at the end of his period, and as he got nothing 

 to feed, his impulse turned in the direction of seeking a place for a new nest. His incubation 

 period is thus seen to be cut short if the egg fails to hatch. The same is true of the crested 

 pigeons. The ring-dove will keep on sitting for 20 days in many cases, or even longer. 

 (SS 10, SS 4.) 



MISCELLANEOUS. 



(1) The pairing of two males, as described in Chapter III, constitutes a defec- 

 tive cycle. Two males may pair, court, unite, and incubate an empty nest. If 

 given eggs, they may hatch them and feed and care for the young. The cycle 

 is thus completed without the presence or production of eggs, and with an unusual 

 and abnormal sexual response. Upon the desertion or death of the female, the male 

 may continue incubation, doing double duty, in spite of the absence of a partner 

 and of her lack of participation in incubation. 



A male will often sit on eggs or young at night, in case the female deserts or dies. An 

 example of the latter has just occurred where a male ring-dove is sitting at night on young 

 only a few days old. 



(2) In a pair of female ring-doves (pair D; see Chapter III), the first egg was 

 laid on January 26. The supposed male attempted to take the nest at this time, 

 but was driven away. He then went to an empty nest and persisted in sitting 

 in spite of being driven off until the act was broken up by covering the nest. He 



