Sex Ratios in Pigeons. 
483 
an equality of sexes in his breeding stock. The same general idea 
is fairly current, and appears from time to time in the pigeon maga¬ 
zines. The article referred to first stated that the difficulty the breeder 
commonly experiences is that at the beginning of the breeding season 
he finds he has an excess of males in the stock he has saved for 
breeding. If this difference is very great it may mean considerable 
loss to a breeder raising squabs for market on a large scale. To avoid 
this difficulty the author made suggestions of procedure based on 
certain definite assumptions, somewhat as follows: (a) A pair of 
squabs, that is a male and a female, is hatched from each comple¬ 
ment of two eggs; (b) the first egg laid produces the male, the second 
egg gives rise to the female; (c) the first egg being laid a considerable 
time in advance of the second, hatches first, and therefore (d) the 
time of incubation being the same for both eggs, it follows that (e) 
the first squab to hatch is a male, while the female hatches sometime 
later; (f) as a consequence of being hatched earlier the male gets a 
start in growth over the female, and consequently (g) the larger squab 
of a brood is a male and the smaller a female. From these assump¬ 
tions the conclusion was drawn that in order to obtain an equal 
number of males and females all the breeder need do would be to 
separate the two members of each brood while he still knew which 
they were, putting the larger squab in each case into one pen and the 
smaller into another. He would then have one pen of males and the 
other of females and he could choose from them to suit his convenience. 
Directions depending upon much the same assumptions are given 
by Wright (1879, p. 33). Speaking of the two eggs of a set he says, 
“These two are in three cases out of four a cock and a hen, but by 
no means always so, as usually supposed; about twenty-five per cent, 
being pairs of one sex or the other. When one is a hen it is generally 
the last of the two, and as such likely to be stunted in growth from the 
earlier hatching of the first, which has had a start by the hen standing 
over it before the other was laid, and thus gets fed and becomes 
larger and stronger before the hen is hatched. To avoid this, laying 
should be watched for every evening, and the first egg taken away 
