MINNEAPOLIS (AP) - Researchers plan to collar 52 adult moose in northeastern Minnesota starting this week in the second year of a high-tech study that seeks a better understanding of why the iconic species is disappearing from the state.
The radio collars use GPS technology and stomach implants to transmit alerts when a moose’s heart stops beating, or if the animal stops moving for six hours, indicating that it likely died. Biologists then try to rush to the carcass within 24 hours before it decomposes or scavengers destroy the evidence.
The idea is to replace the 22 study moose that died over the past year to try to keep the sample at around 100 animals, said Michelle Carstensen, wildlife health program supervisor with the Minnesota Department of Natural Resources. DNR biologists plan to start collaring 36 moose across northeastern Minnesota on Thursday, she said, while researchers for the Grand Portage Band of Chippewa began collaring the first of 16 moose on the reservation for their own study Monday.
DNR researchers also plan to collar 50 moose calves shortly after they’re born this spring. Seventy-four percent of the 49 calves collared last May have died, DNR research biologist Glenn DelGiudice said.
“We’ve got alarm bells ringing on both ends,” Carstensen said. “We’ve got adults dying and a very high calf mortality rate. Neither of these things is good when it comes to wanting to have a stable moose population.”
The DNR’s aerial survey last winter showed Minnesota’s moose numbers continuing to plummet. The population was estimated at 2,760, down 35 percent since 2012 and 52 percent from 2010. The state had about 8,840 moose as recently as 2006. Scientists suspect some combination of higher temperatures, parasites, diseases and changing habitat. While DNR says hunting was not a major factor, it canceled the season, perhaps permanently.
DelGiudice said he’s finishing up this year’s estimate and that it could be released later this week. He declined to say what it will show.
Among the collared adults studied over the past year, the mortality rate was about 20 percent. That’s high compared with non-hunting adult mortality rates elsewhere of 8 to 12 percent, Carstensen said.
Of the 111 adults captured last winter, eight were killed by wolves, including at least three moose that had been weakened by health problems. Two died from infections caused by wolf attacks that they initially survived. Ten died of health problems such as parasites. One developed a fatal infection from a compound leg fracture of unknown cause. One cause of death could not be determined, she said, because all researchers found was the collar.
Four died from complications of being tranquilized and captured, a mortality rate of 3 percent, which Carstensen said was below average.
“Anytime you have to handle an animal it’s a stressful event,” Carstensen said. “We do everything we can to minimize it.”
Eleven calves died soon after being collared, most after their mothers abandoned them, while 20 were killed by predators in their first four months. One more died from in November from an infection caused by a wolf attack, and another’s collar broke off in late December or early January as the collars are designed to do when a calf gets bigger, DelGiudice said.