OREGON VESPER SPARROW 885 



smaller and having the ground color above biiffy brown rather than 

 grayish brown. All the lighter areas of the plumage * * * suffused 

 with pinkish buff." In the juvenal plumage, according to R. R. 

 Graber (1955), P. g. affinis closely resembles P. g. gramineus, but with 

 the black back feathers "only narrowly margined with whitish." 

 The superciliary line is more distinct and complete than in P. g. 

 conjinis. 



The breeding range of P. g. affinis is restricted to the lower valleys 

 and plains west of the Cascade Range in Washington and Oregon. 

 I. N. Gabrielson and S. G. Jewett (1940) report it to be an abundant 

 summer resident in the Wniamette Valley of Oregon, but less common 

 in other coastal valleys. It is an inhabitant of "open meadow and 

 farm lands where it frequents the fence rows and pasture lands" 

 (Gabrielson and Jewett, 1940;, and of "cultivated land and open 

 pastures" (Jewett et al., 1953). In western Washington, summer 

 residents and migrants have been reported from April 4 to September 

 8 (Jewett et al., 1953). J. H. Bowles (1921) reports nests with 

 fresh eggs in Washington from May 9 to June 2. Plural broods are 

 not reported for P. g. affinis. 



The measurements of 40 eggs average 20.7 by 15.2 millimeters; the 

 eggs showing the four extremes measure 22.9 by 16.3, 21.8 by 16.8, 

 19.S by 14.7, and 20.3 by 14.2 millimeters. 



The wintering range of the Oregon vesper sparrow lies west of the 

 Sierra Nevada from central California south to northwestern Baja 

 California, where it overlaps the winter range of P. g. conjinis. 

 Migrants are found occasionally as far east as western Utah (Behle 

 and Selander, 1952). The winter habitat in California is described 

 by J. Grinnell and A. H. Miller (1944) as "Open ground with little 

 vegetation or else areas grown to short grass and low annuals. Bushes 

 and taller grass may be used as retreats or for shelter. Often seen in 

 stubble fields and meadows and along road edges where they forage 

 in a skulking manner." These authors report that the winter 

 residency extends from October to early April; migrants are seen in 

 April and in late August and early October. 



Distribution 



Range. — Western Washington to northwestern Baja California. 



Breeding range. — The Oregon vesper sparrow breeds in western 

 Washmgton (Dungeness, San Juan Islands) and western Oregon 

 (Willamette VaUey, Coos Bay). 



Winter range. — Winters from central CaUfornia west of the Sierra 

 Nevada (Fulton, Lagrange) south to northwestern Baja California 

 (Santo Domingo). 



