52 BEHAVIOR OF PIGEONS. 



52 occurred before 9 a. m., 5 between 9 and 12 a. m., 4 between 12 and 1 p. m., 

 19 between 1 and 4 p. m., and 3 at noon. The proportion of morning hatchings 

 is greater for the second egg than for the first. Of the 34 cases in which the data 

 are given for both eggs of the clutch, 11 pairs were hatched on the same day, 20 

 on successive days, and 3 on alternate days. These data illustrate once more the 

 fact that the incubation period of the second egg tends on the whole to be the 

 shorter; but this phenomenon can not be due wholly to the irregularity of early 

 incubation, because in 4 cases the second egg was hatched first, unless we suppose 

 that the irregularity of incubation not only prevents but positively checks the devel- 

 opment of the first egg. 



METHOD OF HATCHING. 



In hatching, the shell is broken pretty evenly around its large end, so that this is often 

 completely severed, but it sometimes adheres to the body of the shell at one point, and then 

 when the young gets free this cap-like part is often turned into the larger part of the emptied 

 shell. The break in the shell in one case, was 23 to 25 mm. from the small end, or 7 to 

 9 mm. from the large end. This is the usual way in all pigeons' eggs. Only in a few cases 

 have I seen the break nearer the small end than the large end. The egg is usually first 

 pricked about 24 hours or more before the young liberates itself. (R 33.) 



INCREASED INTEREST AT HATCHING. 



Both birds exhibit an increase of interest in the nest at hatching-time. This 

 is not necessarily due to the presence of the young, as it may manifest itself before 

 the eggs are hatched. The phenomenon is mentioned but briefly in several of the 

 records. 



The first egg of a pair was hatched between 5 h 30 m and 6 h 30 m a. m. At 9 h 50 m it was 

 noted that the female has not once left the nest, evidently having an increased interest 

 in the contents of the nest. At ll h 15 m the male, after calling for 2 or 3 minutes on the floor, 

 went to the nest, but the female was loath to leave and he again retired. The female 

 was not off the nest to evacuate during the whole morning, thus showing how much the 

 young has increased her interest in the nest. 1 At l h 05 m p. m. the male went to the nest 

 and the female resigned for the first time. 



At 10 h 45 m a. m. it was noted that the male of a pair of bronze-wings had been trying 

 to get over the eggs for an hour, but the female kept solidly to the nest. Both were evi- 

 dently ready for the young to hatch. At 2 h 30 m p. m., I helped the young bird out of the 

 shell; it was evidently ready to emerge and was impeded by a little unnatural drying and 

 sticking to the shell as a result of an injury on the previous day. On another occasion it 

 was noted that, at the time the young was due to hatch, this male was very attentive and 

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

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

 beside the female, as if he wanted to feed the young before it was quite out of the shell. 



A male mourning-dove sat beside the female most of the time for 3 days before 

 the hatching of the young. The female seemed loath to leave her nest for more than a 

 short time. The male continued to sit close beside the female for 2 days after the 

 first egg was hatched. (R 33, Em 7.) 



1 Normally the female leaves the nest early in the morning, before the first relief by the male, evacuates the cloaca, 

 and then resumes her duty. EDITOR. 



