Page:Bird-lore Vol 05.djvu/172

 How Birds Molt

159

of specimens taken after the breeding season show that molt begins at deﬁ- nite parts of the body and the reclothing extends in deﬁnite directions The wonderfully systematic and gradual renewal of plumage is best seen and

measured in the wings, for a gap appears at the middle of the quill—feathers, extending outward until but three or four primaries remain, then extending inward among the secondaries, so that the new innermost of these and the outermost primary reach maturity at about the same time, It should be noted that the tertiaries (three in small birds, more in others) are partly renewed before the secondaries begin to drop out. The wing-coverts are replaced in alternate rows. There is a time relation between all that goes on in the wings and the growth of body»plumage. which her gins to be melted at a number of points, so many, in fact, that the renewal is traced with some difficulty When the wings are grown, at the end of a month or two, depending upon the size of the bird. the body plumage has also completed its growth As for the tail, usually after the fall of several primaries, the middle pair of feathers drops out, followed rapidly by suc- cessive pairs, so that very often a bird will appear ‘bob-tailed' if the new middle pair is slow in growth Woodpeckers lose the middle pair last. and irregularities are found in other species

At the end of the breeding season every species of bird undergoes a complete molt. Land birds and the Gulls and Waders molt as just described. but water- fowl, that protect themselves by swimming and diving, as well as by ﬂight, such as the Ducks, Grebes. Loans, Guillemots, and others, molt the quill-feathers of the wings all at once, so that for a time the birds are unable to ﬂy. The males of certain bright-

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plumaged species of Ducks are protected for a couple of months by a dull body plumage that begins to appear before their young broods are out of