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Wetmore, Alexander, 1886-, et al. / Warm-blooded vertebrates
(1931)

Chapter II: adaptations for progression by flying ,   pp. 13-24 ff. PDF (4.7 MB)


Page 24


BIRDS
was omitted. In the fall they molted into bright plumage
without the intervening stage of an eclipse dress.
The strange and aberrant forms that feathers may as-
sume are mainly ornamental and may be special plumes
confined to a single sex. Occasionally the barbs of a
feather show little differentiation for more or less of the
length of the shaft. This is true of the seemingly waxen
red tips of some of the secondaries and rectrices in certain
individuals of the cedar and Bohemian waxwings; strange-
ly enough the first feathers of the nestling bird may have
this peculiarity. Of a similar nature are the broader,
hornlike or scalelike feathers seen in the curl-crested
toucan (Beauharnaisius beauharnaisi), and in a cuckoo
from the Philippines (Lepidogrammus cumingi). Other
aberrations include the plumes found in males of many
birds of paradise; the aborted head plumes of a helmet
bird from Borneo (Pityriasis gymnocephala); the tail of
the Reeves pheasant, which may reach six feet in length;
and that of the Japanese silky fowl, the feathers in which,
by some secret treatment, continue to grow without molt
until they attain a length of from twelve to twenty feet.
[ 24 ]


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