Recorded presettlement observations of black-tailed prairie dogs (Cynomys ludovicianus) are not adequate to fully determine their abundance and distribution. Early naturalists and explorers made only casual reports of prairie dogs on an opportunistic basis; their written records do not represent systematic surveys. Cumulative accounts of prairie dog control efforts, together with the known current prairie dog distribution in North Dakota and Montana, clearly show that most journalists failed to record prairie dog colonies. Also, they restricted their travels to a few common routes, and as a result only a very small and select portion of the landscape was surveyed. The hypothesis that prairie dogs dramatically increased in abundance followin...