Page:Territory in Bird Life by Henry Eliot Howard (London, John Murray edition).djvu/202

144 more particularly by one remarkable case, the case of the Cuckoo. The male, after having established himself, utters his call persistently from the day of arrival until approximately the middle of June; but, in contrast with the large majority of species, the female has a characteristic call which she, too, utters at frequent intervals. The female is polyandrous and has a sphere of influence embracing the territories of a number of males; she wanders from place to place, is often silent, and not unfrequently is engaged in dealing with her egg or in searching for a nest in which to deposit it, and therefore she is not always in touch with a male, still less with any particular one. Now there is, much evidence to show that the discharge of the sexual function amongst birds is subject to control, and that this control operates through the female—through her physiological state becoming susceptible to stimulation only at certain periods. So that we have these considerations, that the female is polyandrous, that she has a territory distinct from that of the male, and that her sexual impulse is periodical; and the further consideration that the impulse, since it is periodical, is of limited duration and must receive immediate satisfaction. Such being the circumstances of the case, would the voice of the male serve to insure the union of the sexes at the appropriate moment? Well, the fact that she is polyandrous implies that every male in her sphere of influence is not always capable of satisfying her