TVTIITE-WINGED JTJNCO 1027 



Field marks.- — ^The traveler in the Black Hills and Bear Lodge 

 Mountains during the summer can recognize white-winged juncos as 

 the small gray birds that fly up from the roadside or the forest floor 

 showing prominent white outer tail feathers. Closer observation 

 shows that actually the plumage is predominantly a uniform pearl 

 gray, except for the white wing bars and the white belly. In winter 

 when the white-wing often associates with slate-colored, Oregon, and 

 gray-headed juncos, it can be distinguished from the Oregon and gray- 

 headed juncos by the absence of contrasting reddish-brown on the 

 back and sides, and from the slate-colored junco by the lighter gray 

 plumage and the presence of more white in the tail. The white wing 

 bars are good confirmatory points, but are not striking field marks in 

 most individuals. White-winged juncos are also somewhat larger 

 than the other juncos with which they may be associated. White- 

 wings average 24 to 27 grams, while slate-colored, Oregon, and gray- 

 headed juncos weigh 18 to 20 grams. 



Enemies. — The only reported cowbird parasitism on the white- 

 winged junco was found by A. H. Miller (1948) in southeastern 

 Montana. The cowbird (Molothrus ater) is not a common breeding 

 bird within the range of the white-winged junco, and many other spe- 

 cies of small birds nest in situations much more accessible to the 

 cowbird. 



K. C. Emerson (pers. comm.) has sent me the following list of 

 species of Mallophaga (chewing lice) known from the white-winged 

 junco: Bruelia vulgata (Kellogg) ; Philopterus mirinotatus (Kellogg and 

 Chapman); Ricinus pallidus (Kellogg); Machaerilaemus sp.; Mena- 

 canthus sp. K. O. Malcomson (1960) mentions finding two species 

 of lice, Ricinus hastatus and Ricinus pallidus. 



Fall. — Fall flocking begins on the breeding grounds in mid-July. 

 Harry Behrens tells me that he saw several flocks in the central Black 

 Hills about July 15, 1956. For the most part, however, juncos are 

 seen singly or in small groups until early September. Later in the 

 autumn flocks ranging in size from 10 to 30 individuals are usual. At 

 this time, too, juncos begin to move down from the higher elevations 

 of the Black Hills to the foothills. At elevations of 5,000 feet and 

 over, much of the ground is snow covered from early November 

 until mid-April, but below 4,000 feet much ground is bare. E.. B. 

 Rockwell and A. Wetmore (1914) note that white-winged juncos 

 arrived in the region of Golden, Colo., on October 24 and reached 

 maximum abundance on November 7. 



Winter. — The flocking of white-winged juncos in winter seems 

 similar to that of the better known species of the genus. Juncos 

 frequent feeding tables diu'ing periods of heavy snow cover, but when 

 the ground is clear they sometimes disappear entirely from artificial 



