SEXUAL SELECTION. 
261 
^up. vm. 
'Attractive males. Unless tills result should follow, the 
characters which give to certain males an advantage 
■°Ver others, conhl not he perfected and augmented 
through sexual selection. When the sexes exist in 
exactly equal numbers, the worst-endowerl males will 
ultimately find females (except where polygamy pre- 
vails), and leave as many offspring, equally well fitted for 
their general habits of life, as the best-endowed males, 
f rom various facts and considerations, I fornieily in- 
terred that with most animals, in which secondary sexual 
characters are well developed, the males considerably 
exceeded the females in number; and this does hold 
Rood in some few cases. If the males were to the 
females as two to one, or as three to two, or even in 
a somewhat lower ratio, the whole affair would be 
simple : for the better-armed or more attractive males 
would leave the largest number of offspring. But after 
investigating, as far as possible, the numerical propor- 
tions of the sexes, I do not believe that any great 
inequality in number commonly exists. In most cases 
sexual selection appears to have been effective in the 
following manner. 
Let us take any species, a bird for instance, and 
divide the females inhabiting a district into two equal 
bodies: the one consisting of the more vigorous and 
fitter-nourished individuals, and the other of the less 
vigorous and healthy. The former, there can be little 
doubt, would be ready to breed in the spring before the 
others ; and this is the opinion of Mr. Jenner W eir, who 
has during many years carefully attended to the habits 
ot birds. There can also be no doubt that the most 
vigorous, healthy, and best-nourished females would on 
an average succeed in rearing the largest number of 
offspring. The males, as we have seen, are generally 
■ready to breed before the females ; of the males the 
