The Descent of Man

adults becoming white during the summer. (43.
I am indebted to Mr. Blyth for information as to
the Buphus; see also Jerdon, 'Birds of India,'
vol. iii. p. 749. On the Anastomus, see Blyth, in
'Ibis,' 1867, p. 173.) As an instance of the second
case, the young of the razor-bill (Alca torda,
Linn.), in an early state of plumage, are coloured
like the adults during the summer; and the
young of the white- crowned sparrow of North
America (Fringilla leucophrys), as soon as fledged,
have elegant white stripes on their heads,
which are lost by the young and the old during
the winter. (44. On the Alca, see Macgillivray,
'Hist. Brit. Birds,' vol. v. p. 347. On the Fringilla
leucophrys, Audubon, ibid. vol. ii. p. 89. I shall
have hereafter to refer to the young of certain
herons and egrets being white.) With respect to
the third case, namely, that of the young having
an intermediate character between the summer
and winter adult plumages, Yarrell (45. 'History
of British Birds,' vol. i. 1839, p. 159.) insists
that this occurs with many waders. Lastly, in