PASSERINE BIRDS OF NEW YORK 159 



STONE ('96, p. 1 34), has assumed some black feathers on the lower 

 parts doubtless at the prenuptial moult and is probably an un- 

 usually vigorous bird approaching the plumage of the male as 

 sometimes occurs in other species. 



Molothrus ater (Bodd.). COWBIRD 



1. NATAL DOWN. Olive-gray. 



2. JUVENAL PLUMAGE acquired by a complete postnatal moult. 



Above, including sides of head and neck, wings and tail, dark olive-brown, the 

 feathers edged with pale buff, whitish on the primaries. Below, dull white, 

 buffy on throat, breast and flanks much streaked with olive-brown. Chin 

 white or yellowish. Bill and feet raw umber-brown, darkening to black after 

 postjuvenal moult. 



3. FIRST WINTER PLUMAGE acquired by a complete post- 

 juvenal moult which begins about September first. Unlike the 

 previous plumage, chiefly black instead of brown, young birds 

 becoming practically indistinguishable from adults. 



Above and below, lustrous black with iridescent green and purple reflections. 

 Head, nape and throat purplish clove-brown. Some birds show faint buffy 

 edgings. 



4. FIRST NUPTIAL PLUMAGE acquired by wear, which shows 

 very little, and chiefly in the paler brown of the head. I have 

 seen one specimen which retains a large part of the Juvenal 

 plumage even to the wing quills and the brown feathers are ex- 

 cessively worn as compared with the black ones, acquired at the 

 postjuvenal moult. 



5. ADULT WINTER PLUMAGE acquired by a complete post- 

 nuptial moult in September. Adults are not distinguishable, as 

 a rule, from young birds in first winter dress. 



6. ADULT NUPTIAL PLUMAGE acquired by wear as in the 

 young bird. 



Female. In natal down and Juvenal plumage indistinguishable 

 from the male. Females assume a mouse-gray first winter plum- 

 age by a complete postjuvenal moult and this, modified by wear, 

 is the first nuptial plumage. All later plumages are similarly 

 mouse-gray with indistinct dusky streaks. 



