she certainly is not easily overlooked, for her note is unmistakable even when the behaviour of the male does not betray her arrival.
That the actual presence of the respective females exercised any influence on the course of these struggles is more than doubtful. Not only did one fail to detect them, but one's failure to do so was confirmed by the knowledge that they had not yet arrived in those particular localities. Hence the fact of the male preceding the female is a valuable aid to the interpretation of subsequent behaviour; and one appreciates it the more after having experienced the difficulty of deciding whether she is present during the conflicts between resident males, for no matter how carefully we may observe the conditions which lead up to, and which accompany, such conflicts, or how closely we may scrutinise the surrounding trees, undergrowth, or ground, there always remains the possibility that she may, after all, have been overlooked. But this must not be taken to imply that in such cases direct observation alone can lead to no serviceable result, or that the evidence gained therefrom is worthless. Far from it. Failure to detect a female is so very Common an occurrence that, even if we lacked the corroborative evidence supplied in the life of the migratory male, it would still be unreasonable to suppose that it were solely due to mistaken observation. We mark her absence during the conflicts between the respective males of many common species—the Finches. Buntings, and Thrushes that occupy
