1890.] Probable Causes of Polygamy Among Birds. 1029 
It has been observed that among animals a prepotent male is 
likely to generate more females than males, while in the offspring 
of an impotent male the reverse holds true. This, is it will be 
seen, tends to balance the sexual proportion among polygamists, 
for the overproduction of females by a generation of prepotent 
males would finally exhaust their sexual power by the demands 
of excessive intercourse; and, as a result of the impotency thus 
incurred, the number of young males would increase. Hence 
polygamous sexual intercourse, while tending to extinction of the 
species when carried too far, has within itself a remedy by the 
natural tendency to increase the percentage of males in the next 
generation. This compensatory law, whereby nature seeks, as it 
were, to cure the evil results of polygamous excesses by male 
overproduction, may explain the present state of affairs as cited by 
Darwin and quoted above. Evidently the reformatory process is 
going on at the present day among the species enumerated, be- 
cause the males are yet overtasked by too great preponderance of 
females. We find strong proof of this in the very examples 
given, for in the case of the domestic fowl, whose connubial rela- 
tions are wisely regulated by the careful breeder, a larger per- 
centage of female chicks were produced, while the eggs of unre- 
stricted wild pheasants brought forth four times as many males 
as females. 
Furthermore, it is worthy of note that among highly-orna- 
mented animals virility is excessive. Cock pheasants, restricted 
to a scant number of hens, are sure to abuse them on that ac- 
count, and the canary (Fringilla canaria), a monogamist by nature 
is, by reason of domestication and consequent specialization 
transformed into a modified polygamist, and in case he be not 
provided with more than one mate, she is tormented by his ex- 
cessive amours. Like the turkey cock, male canaries will fre- 
quently destroy both eggs and young, presumably to induce 
“the female to renew the sexual relation. The case of the 
canary is very convincing proof that human interference in 
sexual selection, with a view to higher coloration or improve- 
ment in secondary characters, has actually created excessive 
sexual power and desire, "v the Mc 
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