PASSERINE BIRDS OF NEW YORK 111 



first winter altered only by wear, while others closely allied 

 whether specifically or by habit undergo a more or less 

 complete prenuptial moult, but the fact is incontestable. It 

 is unfortunate that we have so little material illustrating this 

 moult which takes place in so many species while they are 

 away in their southern haunts, their winter wanderings carrying 

 some of them beyond the equator. 



The facts concerning the time of this moult are these. In 

 the vicinity of New York, resident species and birds that winter 

 begin to moult towards the end of March as exemplified by the 

 Myrtle Warbler (Dendroica coronatd) or Ipswich Sparrow (Am- 

 modramus princeps.) A little later such species as the Amer- 

 ican Goldfinch (Spinus tristis) and White-throated Sparrow 

 (Zonotriclda albicollis) begin a moult completed early in May. 

 Many other species that do not winter very far to the south 

 appear to moult in February or March sometimes arriving here 

 with visible traces of recent feather-growth. The most difficult 

 plumages to explain are those of birds which move south early 

 in the autumn before the customary postjuvenal of young birds 

 or the postnuptial of adults has taken place. It seems probable 

 that in these species, which include some of the Swallows and 

 Flycatchers, there is a late postnuptial moult of adults simul- 

 taneous with a partial postjuvenal of young birds the latter in 

 some cases shortly after passing through a complete or partial 

 prenuptial moult. This is the usual sequence in species that 

 moult while with us and a few specimens from far southern 

 counties near the tropics show moult in mid-winter and in 

 spring. The fact that new growth of feathers occurs during 

 the winter in many species is beyond doubt the only question 

 to be solved is, when ? That the postjuvenal and prenuptial 

 seasons of moult overlap, although not in the same species, is 

 proved by numerous specimens of Warblers I have seen which 

 begin to assume their first nuptial dress as early as November 

 and December (in Jamaica, West Indies) although January and 

 February specimens are in more active moult. In some species 

 the prenuptial moult appears to proceed very slowly and 

 irregularly. 



