THE PAIRING OF PIGEONS. 29 



mated two birds on the supposition that they were male and female, and the mis- 

 take was not discovered until the latter part of a reproductive cycle. Sometimes 

 more or less spontaneous mating of females may occur. "Two females, one an 

 ordinary domestic dove and the other an impure fantail, settled in a cot and both 

 laid in one nest and exchanged with each other as if male and female." 



It is probable that females Wl and W2, for which complete records are 

 given in Chapter VII, constitute another case in point. These two female white 

 rings (St. alba) had been purchased in November, 1895, and had been mated on 

 the supposition that they were male and female. The record shows that they 

 had long been together. W2 laid two eggs before being mated with the male X. 

 Wl laid her first egg two days after being mated with X, but he did not respond 

 at once and it was noted in the record that there were probably no unions and 

 it is unlikely that the egg had any chance of being fertilized. Since the two females 

 laid at practically the same time (one day apart), it is very probable that they had 

 united and stimulated each other to the production of eggs. 



An extended account of the behavior of two pairs of female blond ring-doves 

 (pair D, and pair E) will be given. These two matings present most of the 

 phenomena that are to be met with in such matings of female with female. To aid 

 the reader in grasping the intricacies of the detailed account of "pair D," the fol- 

 lowing brief synopsis of events is appended by the editor: 



A first egg was laid during the afternoon of January 24, though the act was not 

 observed. No account of the previous mating activities is given. The second 

 egg was laid at 9 a. m. on the 26th, and this act was observed and described. At 

 this time and during the rest of the day the alleged male persistently tried to take 

 the nest and perform his regular incubation duties. On the next day he failed 

 to exhibit normal masculine behavior, i.e., he did not incubate the eggs during 

 the day and sit on the perch at night; he did, however, behave normally there- 

 after until February 8, a period of 11 days. On the 8th and 9th his behavior was 

 regular, with the single exception that he tried to obtain the nest late in the evening, 

 when he should have been on the perch for the night. A second set of eggs was 

 laid February 27 and 29, and this bird did not begin to exhibit masculine incuba- 

 tion behavior until March 3, when he attempted to assume incubation duties late 

 in the afternoon. On the 5th this alleged male was discovered laying an egg at 

 10 a. m.; and 4 eggs were found in the nest, so that the third egg was probably 

 laid on the afternoon of the 3d, when he attempted to take the nest from the female. 

 The account is given as it was written the bird which was thought to be a male 

 is referred to as a male. * 



For some time before this egg was laid on Jan. 26 the male of "pair D" kept getting 

 into the nest-box 2 and trying to get possession of the nest. After driving him away 

 several times and finding that he was determined to continue his efforts, I gave him a 



1 The two birds of this pair hatched together in the same nest were full sisters as is shown by reference to 

 table 174, Volume II. It is there noted that the "second egg of the clutch was smaller than the first"; this is a rever- 

 sal of the more usual size-relations of the eggs. In view of later work on sex it seems not improbable that the "sup- 

 posed male" described here was hatched from an egg which was less definitely "female" than was the more feminine 

 mate. O. R. 



2 This nest-box was about 8 inches long, 6 inches wide, and 5 inches deep. 



