PASSERINE BIRDS OF NEW YORK 125 



the first winter plumage may be practically complete within a 

 month after the nest is abandoned, the Juvenal having been com- 

 pleted in less than half that period. 



The adults of early nesting species, for example, the Crow 

 (Conws americanus) or Worm-eating Warbler (Helmithtrus 

 vcrmivoms), begin to moult by the end of June when the post- 

 nuptial moult may be said to begin. These represent an ill- 

 defined class of early breeding birds whose young appear to- 

 wards the end of May or earlier and who raise but one brood 

 in the season. Another class comprises the later breeding 

 species raising but one brood hatched towards the end of June 

 like the Bobolink (Dolichonyx oryzivorus] or Wood Thursh (Tur- 

 dns unistelimis}, which moult late in July. A third class com- 

 prises birds that regularly raise two broods like the Song Spar- 

 row ( Melospiza fasciata) or Field Sparrow (Spizella pitsilla), the 

 first appearing towards the end of May, the second in July. 

 The first brood begins the postju venal moult late in August, 

 the second moults in September and October. Belated broods 

 are puzzling and are probably mistaken for third broods by the 

 average observer. It is my opinion that none of our local 

 species regularly raises more than two broods (and few of them 

 more than one) in one season, for a bird taken in nuptial dress, 

 whether accompanied by young or not, when many other birds 

 of the same species show a symmetrical and extensive develop- 

 ment of the moult is suggestive evidence, not of a third, but of 

 a belated brood. My grouping into three classes is purely arti- 

 ficial, however, and only done because it is convenient to think 

 of species thus grouped. 



From what I have already said it is easy to understand what 

 a confusion of moulting birds may be found during July, August 

 and September. The postnuptial moult of adults regularly 

 precedes the postju venal in the same species although young 

 birds may overtake adults in assuming fall plumage if they do not 

 renew the flight feathers. If adults, then, begin a moult in 

 June they complete it in July, if they begin in August they end 

 in September and late-nesting species like the Goldfinch (Spinus 

 tristis] begin in September to finish in October and even No- 



