Conservation of Habitats for Shrubsteppe Birds

Extending over a year, all the birds that could be detected were counted on two transects which together sampled an area of 1.39 km2. Only 37 species were recorded during 82 surveys. Total bird density during the spring (March–June) was 43.0 birds/km2, and the density for the entire year was 26.7 birds/km2. The characteristic nesting birds were Western Meadowlark, Sage Sparrow, Burrowing Owl, Mourning Dove, Horned Lark, Long-billed Curlew, Lark Sparrow, and Loggerhead Shrike. Western Meadow-larks and Sage Sparrows were the most abundant nesting birds, having an average density of 11.2 and 7.8 birds/km2, respectively. Seasonal distribution of birds varied with species, but most species were present only from March to September.

Sixty-three per cent of the habitat surveyed was dominated by Big Sagebrush, 26% was dominated by Cheatgrass, and the remaining 11% was dominated by Spiny Hopsage. Big Sagebrush habitat supported a greater total bird density than the Cheatgrass or Hopsage habitats. Sage Sparrows were closely associated with Sagebrush habitats, while Western Meadowlarks showed no strong habitat affinities.

Extensive habitat modifications induced by more than a century of agriculture and livestock grazing have greatly depleted native Shrubsteppe habitat in the Columbia Basin. Over the past 40 years, the Hanford Site has served as a refugium for Shrubsteppe habitat that supports populations of native Shrubsteppe birds. The concept of the Hanford Site as a refugium for native Shrubsteppe habitat and Shrubsteppe nesting birds is favourably discussed.