for National Geographic News
A midnight survey has shed light on a surprising success story for black-footed ferret reintroduction in Colorado.
The ferrets, perhaps North America's most endangered mammals, have been released in the state since 2001 as part of a national reintroduction program. But Until August scientists had little data to document their success.
"It was a real boost for our morale," said Pam Schnurr, a wildlife conservation biologist with the Colorado Division of Wildlife in Grand Junction.
Biologists searched about half of northwestern Colorado's 20,000-acre (8,000-hectare) Wolf Creek Management Area. Scientists and volunteers walked the rugged terrain for nine nights with high-powered spotlights to spot the reclusive nocturnal animals.
Five ferret sightings were confirmedincluding a lactating female who had given birth earlier in the summer. Another five animals were spotted but not confirmed.
While those numbers might seem low, they suggest that a significant population exists in the region.
"The ferrets are only out for maybe 15 to 20 minutes every two or three nights, so the odds of us coming upon one are low. That's why we were so encouraged with these results," Schnurr said.
"The fact that we saw so many means that there are a lot more out there."
Back From the Brink?
The U.S. Fish and Wildlife Service lists the black-footed ferret (Mustela nigripes) as an endangered species.
The sleek masked predators dine almost exclusively on prairie dogs. Ferrets co-habitate with their prey in extensive underground warrens known as prairie dog towns.
The ferret population took a major hit when prairie dogs came under assault as agricultural pests during settlement of North America's grasslands in the 1920s and '30s.
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