From Wisconsin Department of Natural Resources
-- Dozens of volunteers assisted state wildlife researchers in capturing and placing radio-collars on 132 yearling and adult deer in January, February and March.
Now, the call is going out again for volunteers to help locate fawns born to does that were fitted with implant radio transmitters designed to signal when fawns have been born in mid- to late May.
“With the whitetail birthing season just around the corner, volunteers are needed again to sweep the woods looking for the newborns,” said Chris Jacques, research scientist. “When located, fawns will be fitted with expandable radio collars so we can follow them through their first year of life to determine causes of death, whether it be due to nutrition, environment, vehicle, hunters or predators. This is real applied research and last year’s volunteers found the work rewarding.”
Some hunters have questioned assumptions about fawn recruitment used by wildlife biologists for estimating deer populations. Recruitment is the net addition of new fawns to a population each year, and is an important input in estimating deer population numbers. At the end of this three-year effort to monitor fawns, researchers hope to fine tune their inputs to population estimates based on real-world data collected in this research effort.
Volunteers will be assigned to search teams working in the vicinity of Shiocton in Shawano County and Winter in Sawyer County. When transmitters have been expelled, presumably when a fawn has been born, a search team will form a line and comb the woods, somewhat similar to a deer drive, in search of bedded fawns. Opportunistic searching in high quality fawning habitats also will be conducted across both study areas. Captured newborns will be fitted with a radio collar of their own and left for the doe to raise normally.
If a fawn dies, the collar will emit a unique signal that researchers will again use to locate the animal to determine cause of death. The collars are designed to expand as the deer grows and eventually drop off as the animal approaches its first birthday.
Impact of predators on deer populations of special interest to hunters
“Determining causes of death in fawns is vital to the accuracy of our deer population estimates,” Jacques said. “Of special interest is the impact of predators on fawn deaths. We have a suite of predators in Wisconsin, including black bears, bobcats, coyotes and gray wolves, that may have some impact on yearly fawn production. What we are less certain of are the relative roles that each of these predators may play on fawn recruitment over the course of an entire year.”
During 2011, thanks to the help of volunteers across the state, researchers enjoyed tremendous success capturing fawns. A total of 104 fawns, including 68—48 radio collared, 20 ear-tagged—in the Shawano area and 36—30 radio collared, six ear-tagged—in the Winter area, were captured.
“Though we have collected just one year of field data, preliminary evidence indicates that predation, primarily by black bears and bobcats, is likely having some measurable impact on fawn survival across northern Wisconsin, having accounted for 14 of 22 or 64 percent of deaths during the first month of life,” according to Jacques.
“The predation impact across east central Wisconsin appears to be considerably lower, having accounted for just six of 18 or 33 percent recorded fawn deaths. Vehicle collisions and fawn abandonment appear to be primary causes of death, accounting for half of all recorded fawn deaths in the eastern farmland region. Fawn survival through December 2011 in the northern and east central study areas was 27 and 63 percent, respectively, indicating that the northern forest region is a much tougher place to scratch out a living for fawns than the eastern farmland region of Wisconsin.”
This work is possible with volunteers’ involvement, representing dozens of hunting groups, Jacques said.
“Anyone who has looked for newborn fawns or been startled to discover a fawn lying motionless in the forest or field next to them knows what a challenge it is to find them,” says Jacques. “They have excellent natural camouflage and instinct to remain absolutely still when approached. The transmitters will give us a better idea of where they are but it will still take time on the ground to locate them.”
For more information about the project or to sign up as a volunteer search Deer Research visit http://dnr.wi.gov/org/es/science/wildlife/deer/.
For additional information, contact Chris Jacques at (608) 221-6358 or Bob Manwell (608) 264-9248.