DEFECTIVE CYCLES. 75 



its normal end. The only known external defect was the loss of one egg, but this 

 factor had no appreciable effect upon the incubating impulse for at least 5 days. 

 While the male led in the desertion, the female must have been similarly predis- 

 posed or she would not have responded so quickly to his sexual advances. The 

 following excerpts from the records are apropos: 



Jan. 23. In the morning the male bowed in front of the female, very strongly striking 

 the floor at each bow with his beak. 



Jan. 24. At 4 p. m., both birds were on the floor, hugging, mounting, and strutting, 

 but without contact. 



Jan. 25. Before 11 a. m. both birds have been off the nest several times, and I have not 

 seen the male sitting at all. They are interested in courting and copulating. 



Jan. 26. Hugging, bowing, and "feeding" of the female by the male without coitus 

 occurred in the morning. The egg was finally deserted in the afternoon. Little attention 

 was paid to the egg during the day, and when night came the female did not sit on the 

 egg. Desertion has been gradual with the female. The male has led in the desertion; he 

 enticed the female from her work. This behavior is similar to that observed earlier in 

 the crested pigeons. These cresteds usually sat only a few days and then began over 

 again. In one case the female laid four eggs with but little interruption between the 

 sets. (R33.) 



THIRD CYCLE. 



The incubation record was normal until after the death of the first young on 

 Feb. 20. The egg was injured in handling on the 19th, and the bird died shortly 

 after hatching on the 20th. The male's cycle terminated shortly after this event 

 and he began soliciting the female to renew the cycle. The female resisted his 

 advances until after the death of the second bird, which occurred during the night 

 of the 21st. The birds began copulating on the morning of the following day. 

 The termination of this cycle is evidently connected with the death of their young. 



Feb. 21. Yesterday, at the time the young was due to hatch, the male was very 

 attentive and anxious to have the nest and care. Indeed, he appeared to be remarkably 

 solicitous, and not only tried to get the nest, but called quite a number of times while 

 sitting beside the female, as if he wanted her to get off, and as if he wanted to feed the 

 young before it was quite out of the shell. This morning his behavior is already decidedly 

 changed. He runs over the female and the nest carelessly, and when the female left the 

 second egg for a few moments he at first charged at her, uttering his scolding notes, and 

 then he mounted her twice and went through the routine, but without coitus. I believe 

 that the male was so closely timed with the hatching period that the slip of yesterday 

 (death of first bird) ended his course and that he is now ready to renew another course. 



Feb. 22. The fourth cycle began this morning immediately after the death of the 

 second young. The birds were copulating right away, although no actual union took 

 place at first. 



FOURTH CYCLE. 



The eggs were laid on February 28 and March 2. The male's behavior was 

 slightly irregular from the first, though he participated in his incubation duties. 

 With no apparent external cause, the male gradually terminated the cycle shortly 

 before the eggs were due to hatch. His sexual advances finally broke up the cycle 

 for the female. 



