Sex Ratios in Pigeons. 
501 
clutch that produces a female; (3) that birds kept thus mated and 
overworked at egg-production tend to produce in succeeding years 
fewer and fewer males before the appearance of females. ” 
Since Professor Whitman’s records and notes have never yet been 
published* but are, we understand, being edited for that purpose by 
Dr. Riddle, we do not deem it advisable to enter into an extended 
discussion of these points at this time. Attention should however, 
be directed again to the fact that Cuenot’s results and our own, 
which combined are of considerable magnitude, are directly con¬ 
tradictory to the second of Riddle’s assertions. Furthermore, if 
his other contentions are true, it is surprising how they are masked 
when the statistics are treated in their entirety—it seems, indeed, 
very improbable that the distribution of sexes would balance up so 
as to give such a decided indication of being chance results as has 
been shown to be the case in the present report. More attention 
will be given to this mattei in a subsequent paper, in which the 
data will be considered with respect to the different seasons and 
conditions. 
As one of us has pointed out elsewhere (Cole, 1913) ideas of sex 
determination are often confused by the pigeon breeder with mis¬ 
understood facts of sex-linked inheritance which come up in the 
course of his breeding operations. Because, for example, he finds 
that in certain of his matings a large proportion, amounting in some 
cases to 100 per cent., of the dilute colored offspring (dun, silver or 
yellow) are females, he concludes that in some way sex is being 
determined other than by chance. He does not realize that instead 
of controlling sex he is simply able in certain cases to tell the sex 
of an individual by its color. In this connection, simply by way of 
example, a paper by Martin (1912), entitled “How to control the 
sex of pigeons,” may be mentioned. 
