Bounding from one hole to another, the black-footed ferret's tracks are distinctive -- when conditions are just right to see them.

"We found about 20 ferrets on half of our ranch," said Larry Haverfield, whose 10,000-acre ranch has been at the heart of controversy over prairie dogs and the reintroduction of ferrets, among the most endangered mammals in the United States.

The snow survey, taken in mid December, complements the spotlight surveys that have been made by the U.S. Fish and Wildlife Service in late fall and early spring since the ferrets were reintroduced in December 2007.

Conditions have to be just right, however.

The group of trackers -- utilizing four-wheel-drive vehicles on the ranchland -- got their training from Travis Livieri, director of Prairie Wildlife Research, based in Wellington, Colo.

"They're real distinctive in the snow," Livieri said of ferret tracks.

Because they are short and long, the animals bound through the snow and their "feet land together."

All four feet, in fact, often land in the same spot.

"It's very easy once you know what you're looking for," he said of tracking the animals.

The animals, Haverfield said, will bound from prairie dog hole to prairie dog hole.

During the fall spotlight survey, trackers found 26 ferrets on the Haverfield complex and at the Nature Conservancy's Smoky Valley Ranch where the animals have been reintroduced.

"By the time we got to TNC, the conditions started to deteriorate," Livieri said.

Two additional animals were tracked in the snow on Nature Conservancy property.

The snow tracking, however, came in spots that are less accessible during the spotlight surveys because they include rougher terrain.

To train themselves, Livieri said the trackers went to a spot where ferrets were known to exist.

In addition to finding the animals, the trackers can determine what they have been up to.

"It gives you an unbiased look at what the ferrets did last night," he said of following the tracks.

But it's not an absolute measure.

"Not every ferret comes up every night," Livieri said.

The snow survey helped convince Haverfield that the ferrets are coping.

"It gave me quite a little more confidence we're doing OK," Haverfield said of being able to track the animals.

Livieri agreed.

"I think it gave Larry some real confidence," he said. "Larry seems to be nervous that the ferrets aren't doing very well on his property."

With the snow survey and the spotlighting survey, Livieri said he thinks the Kansas reintroduction project is working.

"I think they're doing pretty good," he said. "I feel pretty confident that effort to establish a population is successful."

It's also a way to measure how many animals might be on the land.

In Haverfield's case, Livieri said, more than twice the number spotted are likely surviving.

"I would say, conservatively, there's double that, maybe 50."