DNR working state’s largest deer study
Dodgeville, Wis. — More than 30 white-tailed deer spilled out of the woods in early March and into the afternoon sun along a quiet valley in north-central Iowa County. They appeared in small groups of two or three until, as shadows lengthened, the alfalfa field filled with grazing deer.
The Southwest Wisconsin CWD, Deer and Predator Study has been labeled the largest and most comprehensive deer research project ever undertaken in Wisconsin. The goal is to conduct a comprehensive examination of factors that impact deer survival and deer population growth in southern Wisconsin. Factors include chronic wasting disease, predation, habitat suitability, and hunter harvest.
The drop net spread out wide before the research team with two pans of corn located near the center of the net trap. The site is one of 40 to 50 potential bait sites in Iowa County. Other net sites dot the landscape in Dane and Grant counties. Some sites are armed with mobile box traps.
“If the baits don’t get hit, we wait until they’ve gone through a cold spell before giving up on them,” said Mike Watt, project coordinator.“ As soon as a property peters out we move on to the next. That way we don’t waste resources.”
The number of staff members involved varies, depending on season and work activities. Money funneled into Wisconsin through the federal Pittman-Robertson Act is a primary funding source.
More than 100 volunteer landowners have offered DNR staff access to their land to conduct operations. The ambitious five-year study targets 100 does, 100 bucks and 100 fawns each year for collaring, a sample size large enough to allow for quality scientific inquiry.
Even into early March the DNR folks still struggled, at times, with bad weather – to them that means warm temps with little snow. As of March 12, 81 deer had been trapped.
On the predator side of the same study, four bobcats and seven coyotes had been captured and collared at that point.
“We like to see colder temperatures and some snow,” said Dan Storm, DNR research scientist.
Not a problem that day – there is a nip in the air as Strom and citizen volunteer Randy Steiner, of Blanchardville, settled into a raised blind.
Storm and Steiner sat quietly for several hours, moving slightly and slowly to loosen stiffening joints. As dusk started creeping across the landscape there seemed to be no interest among the whitetails for the bait. Thoughts of a return visit the next morning seeped in along with the cold as deer appeared on the field, but settled into a feeding pattern several hundred yards to the east.
Then, opportunity knocked. A doe wandered down a wide field road straight toward the trap. Tension mounted as Storm prepared to drop the net, the trigger consisting of two wires used to close a circuit.
“Net down!” Storm barked into his radio. He quickly backpeddled down the ladder of the blind while Watt and his assistant, Mitchell Kern, arrived, swinging into action like medics on a field of battle.
All rushed to immobilize the deer that thrashed around a bit while emitting a loud bawling sound. Two men hugged the animal to the ground while a third administered an anesthetic. It put the deer under just enough to keep the animal calm and pain free.
“I was surprised when I first heard that harsh sound,” Storm noted later. “The deer is scared, but not injured.”
Once sedated, a gentle snoring noise told the scientists the animal was alive and well. What follows is 45 minutes of continuous action until the antidote to the anesthetic is administered, and the deer wanders off unaware of its newly-defined purpose in life.
A tissue sample excised from the rectum will go to the Wisconsin Veterinary Diagnostic Laboratory to check for CWD. A tiny section of the sample will be sent to the USGS National Wildlife Health Center for further research on improved CWD detection methods.
Identification tags are clamped to both ears and a nut driver secures the GPS collar. Collars placed on bucks have an elastic section to allow for swelling during the rut.
“The elastic is sewn into three folds,” Storm said. “As the neck gets bigger, the stitching in the folds will pop to allow for growth.”
A vaginal implant will soon begin emitting a radio signal. The transmitter has a temperature-sensitive switch that changes the pulse rate when the transmitter is expelled at birth.
“This helps us more efficiently catch fawns,” said Watt.
An incisor tooth is extracted after a local anesthetic is administered, a rear leg and girth are measured, and periodic monitoring of vital signs ensures the animal is not stressed by the intrusion. An ultrasound checks body fat along the ridge of back and, for does, a pregnancy check.
Despite the weather, the deer-collaring progress has been good, according to Storm.
“We’ve had occasions when more than one deer is captured by one net drop,” he said.
Juveniles are the most common, those turning 1-year-old this spring. Few deer die as a result of trapping activity. The mortality rate is roughly 2 percent.
Predator captures have been slower than hoped during this first season, however.
“We are considering adapting our approach for predator captures as we move forward,” Storm noted.“We recognize that local trappers who have been active for perhaps 20 to 30 years could be of great help. We hope to explore that option.”
Trapping ends by mid-March as coyotes and bobcats give birth to their pups and kittens are born.
“We will regroup again, likely with adapted approaches, after the denning season,” he said.
The collaring of newborn fawns will begin in late May and early June. Citizen volunteers are needed to help in that effort. Volunteer by contacting Watt or Storm at firstname.lastname@example.org
The DNR will capture 100 deer during each of the next five years, fitting them with GPS collars, and following them for up to five years or until they die from predator attacks, vehicle collisions, hunting, old age, or disease.
Researchers will also trap/collar predators in the two study areas, primarily coyotes and bobcats.
Through March 8, the crew had trapped 81 deer, four bobcats, and seven coyotes with the help of 114 volunteer landowners.
Two study areas are located in Grant and western Iowa counties, and eastern Iowa and western Dane counties.
Deer are captured using one of three methods: drop netting (the most successful), box trapping, and darting with a sedative. When a deer is captured, it is sedated, data is collected, ear tags are attached, a GPS collar is secured on the animal’s neck, the deer is given an anti-sedation drug and released on site.
— Jerry Davis contributed to this report.