. The bird, its form and function . good care of these flight-feathers that theyserve to carry him to his winter home far to the south-ward. But a brood of a dozen or more little Bob-whiteswhose wing-feathers sprout with the most marvellousrapidity, from the moment the birds tumble out of theirwhite shells, would fare ill indeed if they had to trust tothese nurserv^ quills all the first winter, with hungryfoxes sniffing for their scent, and more-to-be-dreaded owlsshadowing their trembling covey. Nature has come totheir aid, and when they have fairly worn out their wingsm the first awkward atte
. The bird, its form and function . good care of these flight-feathers that theyserve to carry him to his winter home far to the south-ward. But a brood of a dozen or more little Bob-whiteswhose wing-feathers sprout with the most marvellousrapidity, from the moment the birds tumble out of theirwhite shells, would fare ill indeed if they had to trust tothese nurserv^ quills all the first winter, with hungryfoxes sniffing for their scent, and more-to-be-dreaded owlsshadowing their trembling covey. Nature has come totheir aid, and when they have fairly worn out their wingsm the first awkward attempts at flight, new featherscome in, and this succession of quills keeps them in fineflying condition until full grown. Indeed so solicitous is 44 The Bird Mother Nature about the ground-nesters that she putsstrength and vigor into the coverts, or upper feathers onthe Uttle wings; so that these shoot forth with an energyfar beyond what is usual, for a time lending their aid inflight, although they are not true primaries. Later they. Fig. 27.—Iridescent feather from the breast of a Rufous Humming-bird, showingwearing off of the tips of the barbs, caused perhaps by rubbing against thepetals of flowers. Magnified 25 diameters. are far outgrown by the flight primaries, and then func-tion only as protectors of these more important feathers. The extreme in this precocious development of chicksis found in those strange Australian birds, the mound-builders, which are left from the first to shift for them-selves; even the duties of incubation being shirked bythe parents. This necessitates a perfect ability on the Feathers 45 part of the young birds to take care of themselves assoon as hatched. They pass the entire first moult withinthe egg itself, and are covered with perfect feathers andfully developed flight-quills when they emerge from theshell. A wild duckling, although provided with a thickwaterproof coat of down, has, like the robin, to wait along time for his flight-feathers; b
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