In some ways, marten can be exceedingly easy animals to study. Put a dab of honey in a live-trap, and these elusive, secretive animals will go after the treat again, and again, and again.

Trapper Jean Legaré, who has helped extensively with a marten study in the southeast Yukon, holds a tranquilized marten. (photo: Jan Adamczewski)

"Most of the marten are quite trap-happy, and lots of them show up six days running -- sometimes in the same trap," said Jan Adamczewski, the Liard regional biologist. "They're in it for the honey," adds Todd Powell, a Yukon government biologist who has been helping with the marten work.

For the last three years, Adamczewski and Powell have been spending a lot of time studying razor-toothed pine marten in the southeast Yukon. They have reams of field data on this important species -- on where they live and what type of forest they prefer, on what they eat and how their weight fluctuates through the year.

Earlier this week, the biologists gave an update on their ongoing work to YTG biologists and other interested parties, making it clear that interpreting all of their information is still a work in progress. "The more we learn about them, the more questions we have," said Powell, who has been responsible for much of the technical field work.

Adamczewski started the marten work in 2001, when he began working with Kaska land stewards. "Much of the intensive work has been done in the land steward area of Linda McDonald, who with her family has cared for the area for many generations," he said. The land stewards -- along with regional trappers -- helped shaped the study from the beginning.

"Marten are by far the most important fur-bearer in the southeast Yukon," said Adamczewski. "Though trapping is down from historic highs, there are still regional trap lines in the area where it is not uncommon for trappers to catch 200 to 300 marten."

These solitary animals seldom venture out into open or logged areas. The forest canopy helps them hide from predators such as owls; they also need downed trees and underbrush where they can take cover and den. In winter, this understory helps them work their way under the snow where they can hunt red-backed voles, often their main prey.

Marten are being used as a focal species for forestry planning in the southeast Yukon. The Kaska Forest Resources Stewardship Council is determining which areas are suitable for logging, and how to balance logging with other values. The council is part of the collaborative forest planning effort between the Kaska and various agencies of the Yukon and federal governments.

While marten have been studied in areas such as Utah and Maine, little is known about this species in the North, where they are typically twice the size of their southern cousins. The only Yukon study on marten was conducted two decades ago near the South Canol Road.

The current study is producing detailed information on individual animals. The researchers weighed every captured animal, took DNA samples, and determined their sex. In the spring they palpated females to see if they were pregnant. They fit 55 marten with radio collars, and tracked them via radio telemetry in order to determine the size of their home ranges. They have conducted numerous track counts to figure out how many marten -- and other animals -- live in a particular area.

Early in the study, Adamczewski met with a group of trappers who had on average 30 years of experience each. He had expected to hear that their best trapping areas were all in lowland forests with big spruce trees, but to his surprise, some trappers said that their upland sites are the most productive ones. (See yourYukon 359: Looking for a marten? Ask a trapper)

"When marten are scarce down low, they may be higher up in the subalpine," said Adamczewski. "That is exactly the opposite of what I would have expected."

Marten are territorial, but figuring out their home ranges has not been easy. Take the case of Cuddles and Anita, neighbouring female marten living in a relatively undisturbed area of forest. The small gentle Cuddles -- who does not even growl when handled -- wanders over more than 50 square kilometres, while the larger Anita sticks closer to home, covering at most 15 square kilometres.

"We have some marten that are real wanderers and some that are nice and tightly packaged," said Powell, adding that they are getting the impression that transients might be common among marten. Some animals show up only once, never to be seen again.

Their studies are taking place in forests near Watson Lake, where logging in some areas has produced a patchy forest with stands of different ages. Most of the clear cuts are small, measuring less than 20 hectares.

Adamczewski said their work to date is showing them that marten can tolerate some logging, if they are left enough habitat nearby. "How marten respond to clear-cut logging depends on how much of the forest is cut, and on what is left behind," he said.

Studies in other areas have shown that once 30 percent of the forest is logged, adult marten largely disappear. Marten might be able to tolerate smaller amounts of logging, particularly if care is taken with the pattern of the openings.

"For example, if 20 percent of a certain area is slated for harvesting, it would be better to cut one big block, or a group of blocks clustered together -- leaving more of the forest intact -- than a whole maze of small blocks," said Adamczewski. "It's better to limit fragmentation, to leave bigger blocks of forest."

The biologists are still teasing out what all of this information can tell them about marten. For example, trapping records indicate that marten populations are cyclical, or at least fluctuate between highs and lows.

One of their goals is to figure out the martens' home range sizes -- summer and winter -- but that could take a few more seasons of field work. "We'd love to tell you a great story about how it is all nice and tidy and that type of thing, but as we all know in biology that is never the case," said Powell. "Putting the whole story together is going to take us a long time."

For more information on the marten project, contact, todd.powell@gov.yk.ca.