the male of this species is provided with three filamentous projections
half as long as the body one rising from the base of the beak, and the
two others from the corners of the mouth. (75. Mr. Sclater,
Intellectual Observer, Jan. 1867. Waterton s Wanderings, p. 118.
See also Mr. Salvin s interesting paper, with a plate, in the Ibis,
1865, p. 90.)
The coloured plumage and certain other ornaments of the adult males are
either retained for life, or are periodically renewed during the summer
and breeding-season. At this same season the beak and naked skin about
the head frequently change colour, as with some herons, ibises, gulls,
one of the bell-birds just noticed, etc. In the white ibis, the cheeks,
the inflatable skin of the throat, and the basal portion of the beak
then become crimson. (76. Land and Water, 1867, p. 394.) In one of
the rails, Gallicrex cristatus, a large red caruncle is developed
during this period on the head of the male. So it is with a thin horny
crest on the beak of one of the pelicans, P. erythrorhynchus; for,
after the breeding-season, these horny crests are shed, like horns from
the heads of stags, and the shore of an island in a lake in Nevada was
found covered with these curious exuviae. (77. Mr. D.G. Elliot, in
Proc. Zool. Soc. 1869, p. 589.)
Changes of colour in the plumage according to the season depend,
firstly on a double annual moult, secondly on an actual change of
colour in the feathers themselves, and thirdly on their dull-coloured
margins being periodically shed, or on these three processes more or
less combined. The shedding of the deciduary margins may be compared
with the shedding of their down by very young birds; for the down in
most cases arises from the summits of the first true feathers. (78.
Nitzsch s Pterylography, edited by P.L. Sclater, Ray Society, 1867,
p. 14.)
With respect to the birds which annually undergo a double moult, there
are, firstly, some kinds, for instance snipes, swallow-plovers
(Glareolae), and curlews, in which the two sexes resemble each other,
and do not change colour at any season. I do not know whether the
winter plumage is thicker and warmer than the summer plumage, but
warmth seems the most probable end attained of a double moult, where
there is no change of colour. Secondly, there are birds, for instance,
certain species of Totanus and other Grallatores, the sexes of which
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