The Clay-colored Sparrow is a common and widespread breeding bird of dry uncultivated prairie-brush regions of the northern Great Plains. Breeding Bird Surveys suggest it is the most numerous passerine of low shrub communities of the northern prairies, especially in the southern parts of the Canadian prairie provinces.
The Great Plains is the continent's most endangered major ecosystem. The decline in extent and quality of North American prairies coincides with decreasing populations of many bird species that depend on them, including the Clay-colored Sparrow. The original vegetation of the northern Great Plains has been greatly modified through human settlement, mainly by conversion for agriculture. The quality of remaining prairies is diminished by fragmentation, invasive plants, suppression of fire, and some livestock grazing practices. In a substantial portion of the Clay-colored Sparrow's range, however, suppression of fire has resulted in proliferation of aspen (Populus tremuloides) woodlands and extensive stands of western snowberry (Symphoricarpos occidentalis) and American silverberry (Eleagnus commutata). It is in these low shrub communities that Clay-colored Sparrows reach their highest densities.
This species has expanded east and north since the turn of the 20th century in response to suitable habitat created by logging and agricultural activities. It is also known to breed in conifer plantations and even in urban/suburban parks. Since 1966, small but significant and consistent declines in breeding populations have been recorded across the central and southern prairie provinces in Canada and, until recently, the Great Plains states. Continued conversion of grassland and shrub communities for agricultural production and urbanization is implicated in these declines.
The first Clay-colored Sparrow was collected at Carlton House on the north Saskatchewan River, in what is now the province of Saskatchewan, by the English explorers Dr. John Richardson and Thomas Drummond in May of 1827. It was shipped back to England and named the Clay-colored Bunting by William Swainson, and the type specimen resides in the University Museum, Cambridge, England.
Clay-colored Sparrows are completely migratory, breeding in the interior of North America and wintering from southern Texas south through Mexico. This is one of the few grassland species to forage off its breeding territory, so defended territories can be very small. Both a nocturnal and diurnal migrant, the species flies low and can be found flocking with a variety of species, particularly conspecifics such as Brewer's Sparrow (S. breweri) and Chipping Sparrow (S. passerina).