00 GENERAL ORNITHOLOGY. 



liighly important special " ilight-feathers " of the wings and " rudder- feathers '' of the tail are 

 to be examined beyond, in describing those members for purjjoses of classification. 



Endysis and Ecdysis Putting on and oflf Plumage. — Xewly batched birds are 



coYered for some time with a kind of down, entirely different from such featliers as they ulti- 

 mately acquire. It is scanty, leaving much or all of the body naked, in most altricial birds, 

 such as are reared by the parents in the nest (Lat. altrix, female nourishei') : but thick and 

 puffy in some AUrices, and in aU Prcecoces (Lat. prmcox, precocious), which run about at birth. 

 Since many birds which recjuire to be reared in the nest axe also hatched clothed, or very speedily 

 become downy, a more exact distinction niay be drawn by using the terma jjtiloj^cpdic and jjsi/o- 

 2)a:dic (Gr. tttlXov, piilon, a feather ; y^/iXoi, psiJos, bare; and nals. pais, a child) respectivody 

 for those birds which are hatched feathered or naked ; a chicken and a canan--bu-d are familiar 

 examples. It is the rule, that the higher birds are burn helpless and naked, recpiiring to be 

 reared in the nest till tlieir feathers grow i the reverse with lower liirds. as the walking, wading, 

 and swimming kinds : and a primary division of birds has even been jiroposed upon this physio- 

 logical distinction. It offers, however, too many exceptions ; thus, no birds are more naked 

 and helpless at birth than young cormorants. Probably all prwcocial birds are also ptilopwdic 

 and all psilopsedic birds altricial; but the converse is far from bedding good, many altrices, as 

 hawks and owls, being also ptih:)pa?dic. In otlier \rords. psilopa?dic bu'ds arc always altricial. 

 but ptilopa?dic birds may be either altricifil or pra-cocial. In any case, true feathers are soon 

 gained, in some days or weeks, those of tlie wings and fail being usually the first to sprout. 

 The accjuisition of plumage is called einh/sis (i'vdva-ir. eiidiisis, putting on). The renewal of 

 plumage is a process familiar to all, in its generalities, under the term " moult," or ecdi/sis 

 (Gr. (KSvais, eJ^dusis, putting off). Feathers are of such rapid gi-o-\vth, and make such a drain 

 upon the vital energies, that we easily understand how critical are periods of the change. 

 The first plumage is usually worn but a sliort time ; then auother more or less complete 

 change commonly occurs. The moult is as a rule annual ; and in nuinv cases more than 

 one moult is required before the bird attains tlic perfection of maturity in its feathering. 

 It is well knoM-n how different many birds are the first year in their coloration from that 

 afterward acquired; sometimes changes progress for soAi'ral years: and some birds appear 

 to have a pieriod of senile decline. All such cliangcs are necessarily coimected. if not 

 with actual moult, as is the rule, then at any rate witli wear and tear and repair of the 

 plumage. The first plumage being gained, under wbateviM' conditions peculiar to the species, 

 it is the general rule, that birds are subject to siiir/le. or aiuuial. moult. Tliis commonlv occurs 

 in the fall, when the duties rf inculiation are concluded, and the well-worn plumatje most needs 

 rerewal. This once-a-year moult, at least, happens to nearly or quite all liirds. Jlany, 

 however, moult twice a year, the additional moult usually occurring in the spriuo-time, when 

 a fresh nuptial suit is acquired ; in such cases, the moult is said to bo doulih-. or sciiii-axiiital. 

 Such additional moult is generally incomplete : that is, all the feathers are not shed and 

 renewed, but more or fewer new ones are gained, with more or less loss of the old ones if 

 any. The most striking ornaments donned for the breeding season, as the elegant plumes 

 of many herons, are usually worn but a brief time, being doffed in advance of the ceneral 

 fall moult. A few birds, as the ptarmigan (Lri(jopiis), regularly have even a third or /njjfe 

 moult, shedding many of their feathers as usual in the early anfunni, then chanainii- 

 entirely to pure white for the winter, then in spring monltins: completely to assume their 

 wedding-dress. As a rule, feathers are moulted so gradually, particularly tliose of the wings 

 and tail, and so simultaneously upon right and left sides (d'the bodv, that birds are at no time 

 deprived of the power of flight. The first flight-feathers a(;([mreA by young birds are usually 

 kept till the next season ; but in those that fly very early, before they are half grown, as so 

 many gallinaceous birds do, their first weak wiug-feathers are included in the general moult 



