While ferret count is down, survival rate seen as strong
Published on -5/11/2012, 11:36 AM
Federal cost of Kansas program nearly $117,000
By MIKE CORN
RUSSELL SPRINGS -- When spotlighters operating under cover of darkness last ventured out onto the High Plains of northwest Kansas, they were only able to find 22 black-footed ferrets at two Logan County reintroduction sites.
But the biologist heading up the project isn't panicking. And there are no plans for additional releases of captive-bred ferrets this year.
The number of ferrets spotted during the two-week survey was down about half from the 38 found last fall, according to Dan Mulhern, a wildlife biologist with the U.S. Fish and Wildlife Service.
But, he argues, it might be the "best survival rate out there."
Mortality rates for ferret males can be as high as 50 percent to 60 percent; female ferrets can be as high as 40 percent.
"If you can get 50 percent survival, that's very good he said. "We expect to go down from fall to spring. We don't expect to go down from spring to fall."
Over time, Mulhern said, the ferret population had been steadily increasing before hitting something of a brick wall, when weather turned extremely dry. That dry weather also reduced the prairie dog populations on the two reintroduction sites.
That reduction of prairie dogs, he said, amounts to about 50 percent from the last time the survey was conducted, which was prior to the reintroduction of ferrets in December 2007.
That survey boosted the cost of the Kansas program for the federal wildlife agency, amounting to about $117,000 in fiscal year 2011, according to Mike LeValley, in charge of the FWS ecological services field office in Manhattan.
That's the figure he reported to Logan County commissioners, who, at a meeting in early April asked what the agency has been paying to support the reintroduction program.
"I gave him what we spent last year," LeValley said of the request for information from Logan County Commission Chairman Carl Uhrich.
The cost covers supplies, equipment and staff time running the program. The money also covers the agency's share of offering free prairie dog control to landowners in a 3-mile radius around each of the two sites.
FWS also pays Kansas State University to monitor prairie dog populations around the two sites.
Last year, LeValley said, the agency conducted an extra study to see what prairie dog numbers looked like in the wake of last year's drought.
The depths of the drought was so extreme that prairie dogs didn't emerge until much later and their numbers were sharply lower.
Mulhern said the survey suggested numbers were down about 50 percent.
"A lot of prairie dogs just did not come above ground," he said. "A lot of them that did come up were not in good shape."
With improved weather conditions this spring, Mulhern said there's a chance for recovery in prairie dogs.
And that should spell improvement for ferrets as well.
As the reintroduction program enters its fifth year, Mulhern and others within the agency will be evaluating its successes.
"We set this up for five years," he said.
The future of the program will likely depend on what the agency finds when it goes back out this fall to once again survey ferrets.
While drought has been a leading cause of mortality, predation has likely increased as well.
Mulhern said coyote numbers are sharply increased from when the ferrets first were released. At that time, coyotes in the area were suffering from a bout with mange, making them susceptible to adverse weather conditions.
"They're pretty tough on ferrets," he said, adding they likely are the top predators of ferrets.
And swift foxes.
"I suspect we'll see swift fox numbers go down," Mulhern said. "They don't eat them. They kill them as competitors."