uite
giddy, when a broken leg occasionally occurs.... Vigorous cocks
'roll' when challenging to fight or when wooing a hen. The cock
will suddenly bump down on his knees (ankle joints), open his
wings, and then swing them alternately backwards and forwards as
if on a pivot. At such a time the bird sees very imperfectly, if
at all, in fact he seems so preoccupied that if pursued one may
often approach unnoticed. Just before 'rolling,' a cock,
especially if courting a hen, will often run slowly and daintily
on the points of his toes, with neck slightly inflated, upright
and erect, the tail half dropped and all his body feathers
fluffed up; the wings raised and expanded, the inside edges
touching the sides of the neck for nearly the whole length, and
the plumes showing separately like an open fan. In no other
attitude is the splendid beauty of his plumage displayed to such
advantage."

In this case it is very suggestive to find that it is the male
ostrich who takes upon himself the task of hatching and rearing the
young. Perhaps this accounts for the female ostrich being able to
dance as well as the male. There are very few examples of birds who
are bad fathers. Often the male rivals the female in love for the
young; he is in constant attendance in the vicinity of the nest; he
guards, feeds and sings to the female, and sometimes shares with her
the duty of incubation. This is done by the male wood-pigeon,
missel-thrush, blue martin, the buzzard, stone-curlew, curlew,
dottrel, the sandpiper, common gull, black-coated gull, kittiwake,
razorbill, puffin, storm-petrel, the great blue heron and the black
vulture. Among these birds it is usual for the family duties to be
performed quite irrespective of sex, and the parent who is free takes
the task of feeding the one who is occupied. As soon as one family is
reared many birds at once burden themselves with another. Audubon
records the case of the blue bird of America, who works so zealously
that two or three broods are reared at the same time, the female
sitting on one clutch, while the male feeds the young of the preceding
brood.[69]

Next in importance to dancing and movement in the aid of courtship
among birds is their use of song and display of decorative plumage.
With them it would seem, even more than among the mammals or with man,
sexual desire raises and intensifies all the faculties, and lifts the
individua