NORTHERN SLATE-COLORED JUNCO 1035 



when older. Bill dusky pinkish buff, flesh-color when older and in 

 dried specimens becoming didl ochre-yellow." 



He describes the first winter plumage as "acquired by a partial 

 postjuvenal moult in August and September, which involves the body 

 plumage and the -wing coverts, but not the rest of the wings nor the 

 tail. 



"Above, including \^ing coverts, sides of head, throat, breast and 

 sides slaty gray, darkest on the crown and veiled mth bistre edgings, 

 especially on the back, more faintly with paler brown or ashy gray 

 on the throat. Abdomen and crissum pure white, sometimes faintly 

 washed with vinaceous cinnamon." 



The first nuptial plimiage is "acquired by wear through which the 

 brown and ashy edgings are finally lost, birds becoming ragged but 

 not much faded by the end of the breeding season. A few new feathers 

 are acquired on the chin early in April, but no regular moult is indi- 

 cated." 



The adidt ^vinter plumage is "acquired by a complete postnuptial 

 moidt beginning the middle of August. Practically indistinguishable 

 from first winter, but the tertiaries usually edged with gray instead 

 of faded cinnamon, the wings and taU blacker and showing everywhere 

 fewer brown edgings." The adult nuptial plumage is acquired by 

 wear as is the first nuptial, from which it is practically indistinguish- 

 able. 



The sexes are indistinguishable in the natal down and ju venal 

 plumages. In first ^vinte^ and subsequent plumages the female is 

 similar to the male, but the gray is much paler and the plimiage 

 everywhere more veUed A\dth brown. 



Wood (1951) throws new light on the amount of white in the 

 junco's three outer tail feathers. The outer pair are always pure 

 white, but the amount of white on the inner two, most notably on 

 the third pair, increases greatly in the fu'st adidt postnuptial molt. 

 Feathers lost or plucked dming the first winter are replaced by 

 feathers having the design of those of the succeeding molt, with more 

 white. 



Food. — Martin, Zim, and Nelson (1951) say "Juncos, like many 

 other members of the sparrow family, are primarily ground-feeding 

 seed eaters. They are partial to seeds of common weeds. In sum- 

 mer, insects constitute about half or more of their diet." For the 

 northern slate-colored jimco "Caterpillars, beetles, and ants seem to 

 be the choice items of the animal diet, the balance being made up of 

 wasps, bugs, grasshoppers, other insects, and spiders." Heading a 

 long list of mostly w^eed plants whose seeds the junco is known to 

 eat, they list those most frequently identified in their stomach con- 



