Sex Ratios in Pigeons. 
477 
greater number of males hatched, may account for the prevailing 
impression of the considerably greater proportion of males among adult 
pigeons. It may be recalled, however, that in the total number of 
pigeons reaching adult age (Period D; see Table I) there was a 
preponderance of males even beyond that at hatching and it is 
natural to ask what has become of these. If we turn to the 233 birds 
“killed, sold or otherwise disposed of” after reaching six months of 
age we obtain considerable light on this point, for only 89 of them were 
females and 144 were males. In other words, we have practically 
equalized the effects of the greater mortality of females by a selection 
favoring males in eliminating birds from the flock. 
There seems then to be real substantiation for the idea that male 
pigeons are commonly in actual excess in adult populations. The 
impression of an excess of males may, moreover, be accentuated 
by certain facts in their behavior. The male birds display their 
sexual characteristics, as a rule, at a considerably younger age than 
do the females. Sexual behavior is, however, far from an invariable 
criterion of sex in young birds; while it presents itself in a positive 
way in many young cocks—by cooing, strutting and fighting—it 
is largely negative in the hens and in the less aggressive or backward 
cocks. As a consequence the breeder soon comes to recognize 
a considerable number of his young males, while the remainder of the 
young stock remains as an undetermined residuum. The males are 
thus more conspicuous, and in this way an impression may be gained 
of a larger proportion of them than actually exists. 
It should be emphasized again in this connection that the data 
here presented pertain only to our own flock. It is possible that 
different results may obtain under different conditions. We believe, 
however, that our conditions are fairly representative in most respects, 
and that the conclusion here reached may be capable of general 
application. 
