HELENA, Mont.—Black-tailed prairie dogs exist on more than double the Montana acreage previously estimated, the state wildlife department has told the U.S. Fish and Wildlife Service as the federal agency considers whether to propose protection for the animal.
A group pressing for Endangered Species Act protection doubts the report that Montana has about 193,800 acres inhabited by prairie dogs, up from an earlier estimate of 90,000 acres.
In a statement, the Montana Department of Fish, Wildlife and Parks said it used “the best science available” and produced “an accurate estimate that shows Montana’s black-tailed prairie dog populations are secure.”
Prairie dogs are elusive and their population strength is gauged by land area, not by a head count, said Ryan Rauscher, the Montana Fish, Wildlife and Parks wildlife biologist who coordinated the survey.
The black-tailed prairie dog is eaten by the endangered black-footed ferret and some other species, and prairie dogs’ burrowing supports denning and nesting by wildlife. Some farmers and ranchers blame the prairie dog for erosion and loss of livestock forage. The Montana Department of Agriculture classifies the animal as a pest, but to Fish, Wildlife and Parks it is a “species of concern.”
The new acreage figure reflects information from aerial surveying, some of it followed by investigation on the ground.
Flights covering 36,000 miles occurred last summer and the data analysis was completed this spring, soon after the 90,000-acre figure was submitted to the Fish and Wildlife Service as a reporting deadline approached, Rauscher said. The larger number has since been sent to the service, he added.
Aerial surveying is among reasons for the big gap between the latest and the previous estimates, Rauscher said Thursday. Earlier work was largely on the ground, he said. Advantages of working from the air include viewing that is not possible on the ground when property owners deny access to their land, Rauscher said.
In 2004, the Fish and Wildlife Service removed the black-tailed prairie dog as a candidate for listing under the Endangered Species Act. Responding to a petition by wildlife advocacy groups, the agency said in December that it would reconsider whether protection under the species law is warranted. A conclusion may be released late this year. If it supports protection, then a separate federal process will begin. Alternatively, there could be a conclusion that protection is not merited, or that it is merited but precluded by higher priorities.
WildEarth Guardians, which petitioned for review of the black-tailed prairie dog’s status, questions methods in the Montana survey. But even if Montana and the other states with prairie dogs calculated accurate estimates, the numbers would not move the animal beyond critical risk, the group’s Lauren McCain said Thursday.
“The threats to prairie dogs have increased and the new surveys that show an increase of acreage in no way demonstrate that the black-tailed prairie dog is out of peril,” McCain said. “There is still over a 90 percent loss of prairie dog range in the last 100 years.”
Black-tailed prairie dogs have been killed by disease, poisoned, shot and displaced by land development.
They exist only in North America. In the United States, they inhabit Wyoming, Arizona, Colorado, Kansas, Nebraska, New Mexico, North Dakota, South Dakota, Oklahoma and Texas, as well as Montana, according to the Fish and Wildlife Service.
Population density varies with season, region and climate, the service said, but typically ranges from 2 to 18 prairie dogs per acre. Occupied habitat is estimated at 2.1 million acres, down from a historic estimate of 80 million to 100 million acres rangewide, the agency said.
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