PASSERINE BIRDS OF NEW YORK 139 



The difficulties of reaching positive conclusions from a small 

 series is well illustrated by this species, especially as the age 

 and sex of some specimens is open to doubt. 



Tyrannus tyrannus (Linn.). Kingbird. 



1. Natal Down. Mouse-gray. 



2. Juvenal Plumage acquired by a complete postnatal moult. 



Above, including wings, dull clove-brown usually darkest on pileum, the feathers of 

 nape and rump obscurely edged with cinnamon, wing coverts edged with pale buff 

 including two indistinct wing bands, secondaries with yellowish white, primaries 

 and tertiaries with dull white ; tail black, tipped with brownish white especially 

 outer rectrices. Below, pure white, a grayish band tinged with buff across 

 jugulum. Bill and feet dusky, becoming black. The first and second primaries 

 are rounded, and without emargination (plate II, fig. 18) and no crown 

 patch exists. 



3. First Winter Plumage acquired by a late postju venal 

 moult which is probably complete, so far as indicated by a few 

 scanty facts. Specimens taken late in August and up to Sep- 

 tember 1 6 show new growth of feathers scattered about the 

 head, throat and back. The head and back evidently become 

 darker, the pectoral band grayer and more diffused and a few 

 yellowish feathers may appear on the crown but the birds 

 seem to pass south before the moult is complete. Birds 

 taken in Central America, unfortunately without dates, show 

 that the species reaches the tropics without any moult of the 

 flight feathers or of the wing coverts and often in full juvenal 

 plumage. It is an interesting problem whether the wings and 

 tail are renewed at the end of the postjuvenal moult or at a 

 prenuptial moult, the former conclusion being most probable- 

 A bird from South America taken March 3 1 (which may pos- 

 sibly be an adult) shows a recently completed moult the sheaths 

 still adhering to the new primaries. More winter material is 

 much to be desired. 



4. First Nuptial Plumage acquired probably by a partial 

 prenuptial moult. This I believe is the true explanation of 

 why birds return in spring in fresh plumage including the two 

 outer emarginate primaries (the shape being indicated on plate 

 II, fig". 19), a new white-tipped tail and the orange crown patch, 



