Editor’s note: Jennifer Vashon is a Canada lynx biologist for the Maine Department of Inland Fisheries and Wildlife.
This winter marked the 11th winter that a field crew from the Maine Department of Inland Fisheries & Wildlife headed north to monitor Canada lynx.
Not only was this another winter of record snow levels, it was also one of the coldest winters we’ve experienced. As early as December, temperatures dipped to below 40 degrees and in January temperature remained around 40 below for a week.
Like past winters, each morning the field crew set off on snowmobiles to check more than 60 cage traps that were set each night to capture lynx. During cold snaps, we closed our traps.
We set traps this winter to recapture six lynx to replace the batteries and acquire the data from their GPS collars.
Recently, we began monitoring lynx with GPS collars. These collars function like the more familiar hand-held or vehicle-mount GPS units. Up to four times each day, our GPS collars communicate with satellites to acquire the animal’s location.
These locations are stored on the collar until we retrieve the collar and download the data. Each collar also is equipped with a motion-sensitive mortality signal that is activated once the animal stops moving for an extended period. This alerts us to the possibility that a lynx has died so we can find the animal, retrieve the data from the collar and examine the site and the animal to determine cause of death.
This winter, our two three-person field crews were led by Scott McLellan, DIF&W mammal group biologist, and experienced contract biologist Eric Rudolph. The field crews included two seasonal field technicians (Jessie Kuester and Lonna Perry) and two volunteers (Brandon Coones and Carmen Vanbianchi).
Between Jan. 21 and April 1, we captured 15 different lynx that included the six lynx we had targeted to replace their radio collars and acquire data. We also captured six adult lynx (five males and one female) for the first time and equipped each with a GPS collar. The three remaining lynx had been captured and equipped with radio collars in the fall and were released from the trap, with the exception of one whose GPS collar had stopped collecting data. His collar was replaced and the animal was released.
This winter, Maine Warden Service pilot Daryl Gordon reported mortality signals from five lynx collars. McLellan and Rudolph led field crews to the mortality sites and determined that three lynx had been killed by fishers, one had died of starvation and another was likely killed by a fisher but too much time had passed to accurately determine cause of death. At the end of the winter field season, we were monitoring 15 lynx that included 13 lynx equipped with GPS collars.
In the spring, adult female lynx give birth to litters of one to five kittens and these kittens stay with the female through the next winter. Thus, each winter, we follow the tracks of radio-collared adult female lynx to count the number of kitten tracks to determine how many kittens have survived.
Last spring, only three adult females were being monitored and none of the females produced a litter. This winter, we were again monitoring two of these three females. Our field crews and David Mallett, a graduate student at the University of Maine, backtracked these two females throughout the winter to verify that they had not produced litters in 2008. Both females were traveling alone.
We also captured two adult females for the first time this winter and we did not observe the tracks of kittens around the capture site, suggesting that these females did not produce litters in 2008 as well. Later in the winter, we backtracked one of these females and verified that she was alone.
Lower snowshoe hare numbers, lynx primary prey, may be responsible for low reproductive rates of lynx on our northern Maine study area. The department is collaborating with the University of Maine and USFWS to document lynx response to lower snowshoe hare numbers.
The department and our partners began this longterm study of Canada lynx in northern Maine to better understand the status and needs of lynx in Maine. Since lynx are federally listed as threatened in Maine and 12 other northern tier states (New Hampshire, Vermont, New York, Minnesota, Michigan, Wisconsin, Montana, Idaho, Colorado, Wyoming, Washington and Oregon), the U.S. Fish and Wildlife Service is charged with developing a recovery plan for lynx.
This plan will determine when lynx have reached the level where protection is no longer necessary under the U.S. Endangered Species Act. The information gathered from our study will be crucial in developing recovery objectives and management actions to lead to the recovery and subsequent “delisting” of lynx in Maine.