of music and dancing performances in birds, nor of the brighter
colors and ornaments that distinguish the male, such an opinion
by no means excludes the conclusion that these phenomena are
primarily sexual and intimately connected with the process of
tumescence in both sexes. It is noteworthy that, according to
H.E. Howard ("On Sexual Selection in Birds," _Zoölogist_, 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