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The status of the white-tailed and Gunnison's prairie dogs was investigated by conducting telephone interviews with agency people knowledgeable about these species within their area of jurisdiction. Available literature on prairie dog taxonomy, and life history and ecology was also reviewed. The white-tailed and Gunnison's prairie dogs are considered distinct species with no recognized subspecies. Both species are colonial, hibernate during the winter, and occur in shrub-grassland and grassland habitats in the Intermountain West. Density of white-tailed prairie dogs within colonies (2-5 prairie dogs per acre) is typically less than densities of Gunnison’s prairie dogs within colonies (5-10 prairie dogs per acre). Wildlife species closely associated with black-tailed prairie dogs are also found in association with white-tailed and Gunnison's prairie dogs. The white-tailed prairie dog occurs from extreme southcentral Montana (1% of the range), south through much of Wyoming (71% of the range) into western Colorado (16% of the range), and northeastern Utah (12% of the range). This represents a potential range distribution of about 40,651,000 acres. The Gunnison's prairie dog occurs in northern Arizona (30% of its range), southwestern Colorado (22% of its range), northwestern New Mexico (45% of its range), and extreme southeastern Utah (3% of its range). The Gunnison's range distribution is approximately 67,121,000 acres. There is no evidence of significant geographic range contraction on a broad scale, but since both species are colonial, loss of colonies during the past century due to poisoning, sylvatic plague, and habitat loss are range reductions. Presettlement populations of both species are unknown, but prairie dog control records for New Mexico suggest the Gunnison's prairie dog was once very common. The decline of the Gunnison's prairie dog from the mid-20th century to the present, due to sylvatic plague, an introduced disease, is documented in the literature. In at least some areas, series of plague epizootics have sequentially reduced Gunnison's prairie dog populations to low levels. The two largest white-tailed prairie dog complexes, one in Wyoming and one in Colorado/Utah, have been influenced by plague, as well. For both species, some survivors of plague epizootics have tested sero-positive for plague, suggesting the potential for genetic resistance to plague. Plague is clearly the most significant factor affecting prairie dog populations range-wide for both species. Limited prairie dog poisoning continues on private land, but there were no reports of recent organized government-sponsored programs to eradicate prairie dogs from large areas. Recreational shooting of both species does occur, but in most areas it is considered as a secondary population impact. Colorado and Arizona have recently restricted prairie dog shooting on public lands at least during spring, and Utah has restricted shooting of Gunnison's prairie dogs. Loss of habitat due to agricultural land conversion and urbanization is important on a local scale, but is not considered a significant range-wide impact. Individual agency reports with varying levels of empirical support, suggested that white-tailed and Gunnison's prairie dog populations are generally stable to declining. Plague was frequently cited as a recurrent event and was identified as the cause of declining populations or the factor preventing populations from increasing. Outside of black-footed ferret reintroduction areas in Wyoming, Colorado, Utah, and Arizona, there is little current information on prairie dog occupied acreage and trend for either species. Many prairie dog colonies have been mapped over the past two decades in relation to specific energy projects, but most of these data are now antiquated and have not been incorporated into a single data base. There is a need, especially with the Gunnison's prairie dog, to conduct a range-wide population inventory.


Prepared for: National Wildlife Federation and Environmental Defense