PASSERINE BIRDS OF NEW YORK 143 



the breeding season the plumage becomes excessively worn and 

 ragged, pale brown prevailing above, and below a dirty mottled 

 white produced by exposure of the grayish bases of abraided 

 feathers. 



5. ADULT WINTER PLUMAGE acquired by a complete post- 

 nuptial moult, beginning after August I5th. Adults are per- 

 haps a trifle darker than young birds, especially the remiges. 



6. ADULT NUPTIAL PLUMAGE acquired by wear, as in the 

 young bird. 



Female. The sexes are alike and the moults correspond to 

 those of the male. I have examined birds taken every month 

 in the year, both males and females. 



Contopus borealis (Swains.). OLIVE-SIDED FLYCATCHER 



1. NATAL DOWN. No specimen seen. 



2. JUVENAL PLUMAGE acquired by a complete postnatal moult. 



Above, together with sides of head the throat and flanks deep olive-brown, pileum, 

 wings and tail deep clove-brown ; sides of rump, white ; wing coverts edged 

 with ochraceous-buff, tertiaries tipped with brownish white, sides of rump and 

 flanks white. Below, primrose-yellow, narrowed to a median line on the breast 

 by olive-brown streaking on throat and sides. Bill black, the under mandible 

 buff centrally. Feet bistre, black when older. 



3. FIRST WINTER PLUMAGE acquired by a late postjuvenal 

 moult beginning in September which possibly is complete. I 

 have seen no extra-limital specimens 'but I should expect to 

 find them retaining the brown wing edgings. Pale wing bands 

 are probably acquired at this moult when young birds become 

 practically indistinguishable from adults. 



4. FIRST NUPTIAL PLUMAGE acquired apparently by wear. 

 Birds return from the south in fresh little worn plumage, the 

 young birds with a dull clay-colored lower mandible. Old worn 

 feathers may be found mixed with the new in some specimens, 

 very strongly suggestive of a recent limited prenuptial moult. 



5. ADULT WINTER PLUMAGE acquired by a complete post- 

 nuptial moult seldom begun until the birds have migrated south- 

 ward in September. A specimen from Pinal County, Arizona, 



