KITES, HAWKS, AND EAGLES: Family Acctpitriidae [189] 



which found that two had fed exclusively on meadow mice (Microtus 

 nanus canescens) and one on Columbian ground squirrels (Citellus colum- 

 bianus^). This is the usual result of such examinations. 



Swainson's Hawk: 



Buteo swainsoni Bonaparte 



DESCRIPTION. ''Adult male in normal plumage: throat and belly white, white of throat 

 sharply contrasted with reddish brown chest band; upper parts nearly uniform dark grayish 

 brown; tail crossed by about 9 or 10 narrow blackish bands. Adult female in normal 

 plumage: like male, but chest patch grayish brown instead of rufous. Melanistic 

 phase, both sexes: whole plumage uniform sooty brown, under tail coverts sometimes 

 spotted or barred with rusty or whitish. Every possible gradation is shown by 

 different individuals between this black phase and the light colored normal plumage. 

 Young: upper parts blackish brown varied with buffy or yellowish brown, head, 

 neck, and under parts buffy brown, head and neck streaked with blackish; under 

 parts usually more or less blotched with blackish. Male: length 19.50-10.00, 

 extent 48.00-50.50, wing 14.40-16.00, tail 8-9, bill .80-. 90. Female: length 2.1-2.2., 

 extent 50.50-56.00, wing 14.75-17.15, tail 9-10, bill .80-. 90." (Bailey) Nest: A 

 bulky mass of sticks, lined with leaves and bark, usually in cottonwood or juniper. 

 Eggs: i to 4, greenish white, sparingly spotted with brown. 



DISTRIBUTION. General: Breeds from British Columbia (east of Cascades), Fort 

 Yukon, Great Slave Lake, and Manitoba south to Mexico. Winters in southern 

 South America. In Oregon: Common summer resident in all counties east of Cas- 

 cades. Arrives in March and remains until September. Occurs in western Oregon 

 only as a straggler. 



SWAINSON'S HAWK was described from a specimen taken near Fort Van- 

 couver, Washington, but at present is only a straggler anywhere west of 

 the Cascades. There is a specimen in the Biological Survey collection, 

 taken at Corvallis in 1899 by A. H. Higginson, and there is one in the 

 University of Oregon collection from Lane County. The species was first 

 reported from Oregon by Cassin (Baird, Cassin, and Lawrence 1858) as 

 found in 1854, and Bendire (Brewer 1875) collected eggs in Harney Valley. 

 Shelton (1917) considered it a breeding bird in the Willamette Valley, 

 but we have no evidence to substantiate this statement. In eastern Ore- 

 gon, where it has been one of the most abundant nesting raptorial birds, 

 it can still be considered a common summer resident, despite a noticeable 

 decrease in its numbers in recent years. Our earliest record is March n 

 (Wasco County); and our latest, October 15 (Harney County). Like other 

 hawks, this one has a marked variation of plumage. Melanism is quite 

 common, and all variations of darkness are found, some of them being a 

 curious chocolate color. The young birds are a peculiar buff tone beneath 

 with longitudinal brown stripes quite unlike their parents. 



The favorite nesting site is one of the gnarled twisted junipers grow- 

 ing in the sagebrush. There a bulky mass of sticks is built, sometimes 

 close to the ground and usually not over 2.0 feet up. The nests are used 

 for years if the birds are not molested, and the gradual accumulation of 



