_. "Here in Heligoland,"
he says, "the forerunners of the spring migration are invariably old
males; a week or two later, solitary old females make their appearance;
and after several weeks, both sexes occur mixed, _i.e._, females and
younger males; while finally only young birds of the previous year are
met with." Newton alludes to it as follows:--"It has been ascertained by
repeated observation that in the spring movement of most species of the
northern hemisphere, the cock birds are always in the van of the
advancing army, and that they appear some days, or perhaps weeks, before
the hens"; and Dr Eagle Clarke, in his _Studies in Bird Migration_,
makes the following statement:--"Another characteristic of the spring
is that the males, the more ardent suitors, of most species, travel in
advance of the females, and arrive at their meeting quarters some days,
it is said in some cases even weeks, before their consorts." Some
interesting details were given in _British Birds_[1] in regard to the
sex of the migrants that were killed by striking the lantern at the
Tuskar Rock, Co. Wexford, on the 30th April 1914. In all, there were
twenty-four Whitethroats, nine Willow-Warblers, eight Sedge-Warblers,
and six Wheatears; and on dissection it was found that twenty
Whitethroats, seven Willow-Warblers, eight Sedge-Warblers, and one
Wheatear were males.

What a curious departure this seems from the usual custom in the animal
world! Here we have the spectacle afforded us of the males, in whom
presumably the sexual instinct has awakened, deserting the females just
at the moment when we might reasonably expect their impulse to accompany
them would be strongest; and this because of their inherited disposition
to reach the breeding grounds. If, in order to attain to reproduction,
the male depended primarily upon securing a female--whether by winning
or fighting matters not at the moment--if her possession constituted the
sole difference in his external environment between success and failure,
then surely one would suppose that an advantage must rest with those
individuals which, instead of rushing forward and inflicting upon
themselves a life of temporary isolation, remained with the females and
increased their opportunities for developing that mutual appreciation
which, by some, is held to be a necessary prelude to the completion of
the sexual act, and to which close companionship would tend to impart a
stimulus.

In thus speaking, ho