BREWERS SPARROW 1209 



I am considering the two named races, breweri and taverneri, 

 together here because the paucity of life history data warrants no 

 separation and, in fact suggests an essential uniformity in the habits 

 and beha\nor of the two forms. (S. b. taverneri differs from nominate 

 breweri in ha\nng broader black streaks on the back, a darker gray 

 breast, a slightly longer tail, and a shorter, stubbier bili. 



The race breweri breeds within the continental United States, 

 excluding Alaska, and the more southern portions of western Canada. 

 It is often the most common summer resident in open, brushy habitats 

 of the Sonoran and Transition zones in these regions, where many 

 authors have noted its close association with sagebrush (Artemesia 

 tridentata) . J. Grinnell and A. H. Miller (1944) write that in Cali- 

 fornia, where the species breeds within an altitudinal range of 350 to 

 10,400 feet, it may even follow the Artemesia association into the 

 Boreal zone. Although the relationship between bird and plant is 

 close, the presence of the latter does not imply the former, nor are 

 there any indications of an obUgative relationship. For instance, 

 R. E. Snodgrass (1940) records that in Yakima and Franklin counties. 

 Wash., Brewer's sparrow is replaced by the chipping span-ow in 

 sagebrush desert habitats; L. Wing (1949) found them in considerable 

 abundance in bunch grass prairie; and Wauer (1964) records them 

 breeding in pinon pine-juniper woodlands. S. b. breweri breeds south 

 throughout the central plateau of Mexico to Jalisco and Guanaguato, 

 where it goes under the name of "chimbito de Brewer" (A. H. Miller, 

 1957). 



Just as breweri is characteristic of the arid sagebrush, the slight!}' 

 larger, more northern race, Spizella breweri taverneri, formerly known 

 as the timberUne sparrow, is typically associated with the balsam- 

 willow habitat of southwestern Yukon, northwestern and central 

 British Columbia, and the Canadian National Park regions of Banff 

 and Jasper. H. S. Swarth and A. Brooks (1925), who described the 

 race, call it "an inhabitant of the Alpine-Arctic zone on mountain 

 tops," and they and subsequent observers have found it breeding 

 above timberline. Although these races are not known to overlap 

 during the breeding period (I. M. Cowan, 1946), a population of 

 breweri living at 6,000 feet in the Lassen Peak region of California 

 was found by Grinnell, DLxon, and Linsdale (1930) to approxunate or 

 even dupUcate most of the peculiarities of tavemeri's coloration. 

 This fact suggested to the above authors "a 'tendency' in birds from 

 the extreme northwestern outposts in the general range of breweri 

 toward taverneri." 



Nesting. — In its typical haunts of exposed scrub vegetation, whether 

 on the desert to the south or above the timberline in Canada, Brewer's 

 sparrow acts in a shy, retiring manner, and if its nest is approached 



