Researchers track marten success in northern Wisconsin
By Tanya Aldred, GLIFWC Wildlife Biologist
Odanah, Wis.—This past winter GLIFWC staff collaborated with professors from UW-Madison and wildlife staff from the US Forest Service and Department of Natural Resources to conduct a study on waabizheshiwag (martens) in northern Wisconsin. The objectives of the study are to measure the success of the American marten stocking effort that was conducted from 2008 through 2010 in the Chequamegon Marten Protection Area (MPA) and surrounding area using genetic methods. Single-sample hair snares were used to collect hairs from martens at 200 sites across the Chequamegon-Nicolet National Forest.
"This information will help us genotype the 90 martens stocked in Chequamegon MPA and determine if stocked martens are reproducing successfully," said Jonathan Pauli, Assistant Professor at UW–Madison. "We'll also determine if the stocked martens are breeding amongst themselves and/or with establish 'resident' martens." Pauli and his lab extracted the hairs from all the brushes sent to them, identified the species based on certain characteristics of the guard hairs, and finally, extracted DNA from the hair follicles.
The techniques used in this type of research are important in order to study such an elusive species. Since endangered species are difficult to monitor due to high cost of field equipment and challenges associated with winter field work, new and more cost effective techniques have changed the way wildlife biologists collect data. Some of these more non-invasive techniques include conducting track counts, deploying trail cameras and setting hair snares. In order to estimate marten populations and determine the success of marten reintroductions, the use of non-invasive sampling techniques and genetic-based sampling designs are becoming an extremely useful tool in wildlife management.
Setting snares: the technical low-down
The hair snares consist of a 4" diameter PVC tube, blocked at the back end, and a polycarbonate front door screwed to a hinge attached to the tube. A monofilament nylon line was tied to the bait at the back end and tied to a cotter pin which was used to hold the door open. By using the monofilament line attached to bait inside the snare, we expect the marten to crawl inside to get at the bait, thereby pulling the cotter pin out of the door and the door would close. However, the door is on a hinge opening outward, therefore the marten can still get out of the trap, but the door would then close behind it as it exited the trap, ensuring no other animal could get inside, therefore, making it a single-sample hair trap. Steel brushes were placed inside the snare to collect the hair samples.
At each location we identified an appropriate place to deploy the hair snare (i.e. under/along a fallen tree, under/near stump or tip-up). Each location was marked with a GPS unit and the UTM coordinates. Cover type, snare location and lure used were recorded on a datasheet. The sites were labeled with flagging tape for ease of locating at later dates. Each snare was set in a sturdy position to ensure it wouldn't roll or tip over if visited by a marten. Snares were baited with various kinds of frozen meats or jam with several drops of crayfish oil applied to the bait.
Gusto, a commercial scent, was used to lure animals to the snares; it gives off a strong essence of skunk. When checking the hair snares, we inspected each trap to look for signs that a marten may have visited the snare, such as prints in the snow. If the door looked as though it had been tripped or used, we carefully extracted the trap and removed the metal brushes wearing latex gloves and inspected each brush for hair samples. The used brushes were placed in a toothbrush holder and were labeled with the date and species. The used traps were then rebaited and set again. Although these snares were intended to lure in martens, they were also visited by other wildlife species such as akwaanawe nenaapaajinikeshinh (short-tailed shrew), miskwaa ajidamoo (red squirrel), zhingos (ermine/short-tailed weasel), ojiig (fisher) and gidagaabizhiw (bobcat).
GLIFWC Wardens Lauren Tuori and Dan North also assisted in the study by providing transportation to hair snare sites that were located off-road or on snowmobile trails.