, according to
H.E. Howard ("On Sexual Selection in Birds," _Zooelogist_, Nov.,
1903), color is most developed just before pairing, rapidly
becoming less beautiful--even within a few hours--after this, and
the most beautiful male is most successful in getting paired. The
fact that, as Mr. Hudson himself points out, it is at the season
of love that these manifestations mainly, if not exclusively,
appear, and that it is the more brilliant and highly endowed
males which play the chief part in them, only serves to confirm
such a conclusion. To argue, with Mr. Hudson, that they cannot be
sexual because they sometimes occur before the arrival of the
females, is much the same as to argue that the antics of a
kitten with a feather or a reel have no relationship whatever to
mice. The birds that began earliest to practise their
accomplishments would probably have most chance of success when
the females arrived. Darwin himself said that nothing is commoner
than for animals to take pleasure in practising whatever instinct
they follow at other times for some real good. These
manifestations are primarily for the sake of producing sexual
tumescence, and could not well have been developed to the height
they have reached unless they were connected closely with
propagation. That they may incidentally serve to express
"gladness" one need not feel called upon to question.

Another observer of birds, Mr. E. Selous, has made observations
which are of interest in this connection. He finds that all
bird-dances are not nuptial, but that some birds--the
stone-curlew (or great plover), for example--have different kinds
of dances. Among these birds he has made the observation, very
significant from our present point of view, that the nuptial
dances, taken part in by both of the pair, are immediately
followed by intercourse. In spring "all such runnings and
chasings are, at this time, but a part of the business of
pairing, and one divines at once that such attitudes are of a
sexual character.... Here we have a bird with distinct nuptial
(sexual) and social (non-sexual) forms of display or antics, and
the former as well as the latter are equally indulged in by both
sexes." (E. Selous, _Bird Watching_, pp. 15-20.)

The same author (ibid., pp. 79, 94) argues that in the fights of
two males for one f