gallinaceous birds in the East, he thinks that such slight differences
are beneficial. For myself, I will only say that I am not convinced.
Formerly when I was inclined to lay much stress on protection as
accounting for the duller colours of female birds, it occurred to me
that possibly both sexes and the young might aboriginally have been
equally bright coloured; but that subsequently, the females from the
danger incurred during incubation, and the young from being
inexperienced, had been rendered dull as a protection. But this view is
not supported by any evidence, and is not probable; for we thus in
imagination expose during past times the females and the young to
danger, from which it has subsequently been necessary to shield their
modified descendants. We have, also, to reduce, through a gradual
process of selection, the females and the young to almost exactly the
same tints and markings, and to transmit them to the corresponding sex
and period of life. On the supposition that the females and the young
have partaken during each stage of the process of modification of a
tendency to be as brightly coloured as the males, it is also a somewhat
strange fact that the females have never been rendered dull-coloured
without the young participating in the same change; for there are no
instances, as far as I can discover, of species with the females dull
and the young bright coloured. A partial exception, however, is offered
by the young of certain woodpeckers, for they have the whole upper
part of the head tinged with red, which afterwards either decreases
into a mere circular red line in the adults of both sexes, or quite
disappears in the adult females. (12. Audubon, Ornith. Biography,
vol. i. p. 193. Macgillivray, History of British Birds, vol. iii. p.
85. See also the case before given of Indopicus carlotta.)
Finally, with respect to our present class of cases, the most probable
view appears to be that successive variations in brightness or in other
ornamental characters, occurring in the males at a rather late period
of life have alone been preserved; and that most or all of these
variations, owing to the late period of life at which they appeared,
have been from the first transmitted only to the adult male offspring.
Any variations in brightness occurring in the females or in the young,
would have been of no service to them, and would not have been
selected; and moreover, if dangerous, would have been eliminated. Thus
the females and the young will either have been left unmodified, or (as
is much more common) will have been partially modified by receiving
498