During the last several decades, wild turkeys have spread northward through Minnesota, probably far beyond their ancestral range. How much farther can they go? Several researchers are trying to provide answers, by pushing turkeys into new areas.
Two years ago, DNR area wildlife supervisor David Pauly set out to test winter survival of wild turkeys by releasing 25 radio-tagged birds near Bock, well north of the turkeys native range. Last summer, three turkeys still returned radio signals. That number may seem modest, but a single fertile hen can rear 10 to 15 poults.
"Local residents continue to report turkey sightings, most likely descendants of the radio-tagged turkeys," said Bill Faber, a wildlife ecologist who joined the operation following the pilot study.
Since that pilot project, Faber, St. Cloud State University graduate student Dale Kane, and DNR wild turkey biologist Dick Kimmel devised a plan to monitor turkeys in several areas in east-central Minnesota. Their goal: to determine how far north the birds could survive and whether their range could be extended through the use of supplemental food plots.
During February and March 2002, a DNR turkey trapping team captured 79 birds from Whitewater Wildlife Management Area and Forest Lake. The turkeys were tagged and released in Snake River State Forest, Bradbury Creek area, and near Foreston and Bock. Most were hens. The others were a mix of mature toms and immature "jakes." Only hens were fitted with radio collars, Kimmel said, because females are more vulnerable to bad weather. The transmitters operate in "mortality mode"the signal changes if the bird remains motionless for more than seven hours.
Based on the tracking of "dead bird" signals, researchers discovered that predation, not starvation, was the number one killer of turkeys in 20012002, a mild winter. Bobcats were the most frequent predator. During the more severe winter of 20002001, starvation was the leading cause of death.
Cold alone did not affect turkey survival, but snow was a major danger. As snow depth exceeded 10 inches, covering most food sources, starvation rates mounted, Faber said. Undernourished turkeys became easy prey for predators.
The researchers discovered that turkeys had a better chance of survival if released near supplemental food plots. Two release sites were near standing corn; two others had no extra feed.
The project will continue this winter and spring, with money from the DNR, National Wild Turkey Federation and its Minnesota chapter, and Mille Lacs Band of Ojibwe.
"Plans are to increase the sample size back to 20 birds on each of the four study areas," said Kimmel. "Were going to continue to study the winter survival of turkeys in their northern range, and try to determine if supplemental feeding truly enhances survival.
"At that point, we hope to look at the productivity [breeding] differences between turkeys in natural food study areas versus supplemental food study areas, and determine exactly what those natural foods are too."
Wild turkey experts will discuss this and other turkey research at the Northern Wild Turkey Workshop, Jan. 1618, in Bloomington. The public is welcome to attend presentations Jan. 17. For more information, call 507-642-8478, ext. 25.