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• and yellowt~-oat. Of t'.:ese species, only the yellowthruat was observed in <br />sufficient numbers to ex?iibit an af`i.:uty for the type. <br />Leland sagebrush. The sagebrush vegetation type supported a total of eight <br />passerine species during the June, 1979 census. The violet-green swallow <br />and red-winged blac',;bird were the Trost abundant species observed. The <br />sacebivsh habitat supported the lowest total avian population of all types <br />samples (22.7 individuals/:~r). The Shannon-Weiner species diver- <br />sity index (1.52) was relatively hioh because the number of observations rras <br />equally c'sstributed airong species. Bullock's oriole and the barn swallow <br />were observed only in the sagebrush; however, neither were observed in <br />s~.:fficient numbers to indicate an affinity for this habitat. <br />Grassland pasture. The grassland pasture vegetation type was the most hocro- <br />aeneous ~•egetation type sa:rq~led and accordingly, the least diverse in terms <br />of ntsnters of bird species observed (4). The western meadowlark represented <br />at least 753 of all sightings during the June, 1979 census. Due to the low <br />• number of species observed and the dominance by the western meadowlark, the <br />Shannon-Weiner species diversity indE:x in this type was lowest (0.69) of <br />all types sampled. The total avian population supported by this habitat <br />was 26.0 individuals/lar, the lowest of all species sampled after upland <br />sagebrush (22.7 individuals/]an). <br />Important breeding passerine birds. Twenty-two different avian species <br />were encountered alono t1e breeding bird transects conducted in the five <br />vegetation types surveyed. Abundant passerine species in decreasing order <br />of relative abundance during June, 1979 census were: red-winged blackbird, <br />violet-green swallow, concrnn crow, and western meadowlark. All of these <br />species except western meadowlark were observed in at least four of the five <br />vegetation types sampled. <br />Red-winged blackbird. The red-.,ringed blackbird was the most abundant species <br />obser•/ed on i:he study a.-ea averac.no 19.5 invididuals/Im: over all habitats. <br />This ubiquitous species was encountered on all fi~,e vegetation tyres and was <br />. the rest abundant species in each type. The red-winged blackbird is gre- <br />garious and `ends, flys a*!d roosts in flocks. It was rrost abundant in rinar- <br />i~n and al:aif=. field ~w'~itats and shaved an affinity for these types. <br />-33- <br />~uN ~ i ~aeo <br />