Click above to learn why a study lasting more than one year provides better information and potential answers.
Data collected from the first two years of a multi-year study to learn more about the causes of death in adult moose in northeast Minnesota has given wildlife researches an unprecedented view into moose survival.
The study, which began in January 2013, is unique because it uses high-tech GPS collars to transmit information about an animal's movements through the Iridium satellite system to researchers' computers. When a moose dies, a text message and email are sent from the moose's collar to a team of trained responders.
The goal of the study is to determine causes of death in Minnesota's moose to enhance our understanding of what factors may be responsible for the population's recent decline.
Although still early in the study, we have documented two very different years, in terms of moose survival.
During the first year, 20 percent of collared moose died. This is nearly twice as high as other North American moose populations that are either stable or slightly increasing. An annual mortality rate of 8-12 percent is normal. Causes of death included 11 predator-related (52 percent) and 10 health-related mortalities (48 percent), including brainworm (Parelaphostrongylus tenuis), winter ticks (Dermacentor albipictus), bacterial infections and other undetermined causes.
In the second year of the study, only 11 percent of moose have died. Causes of death included six predator-related (55 percent) and five health-related (45 percent) mortalities, which include brainworm, accident (fell through the ice) and other multiple, chronic health issues. Importantly, there were no deaths associated with winter tick infestations, likely due to the prolonged winter of 2013, where tick numbers were likely reduced.
As this study continues, understanding how environmental variation, predator abundance and fluctuations in parasite loads impact moose survival will provide more insight into which factors may be driving this system.
Additional adult moose will be collared this winter and 50 more newborn moose calves will be collared in this spring. Without the information and insight the study can provide, there is little hope that these massive and majestic animals will continue to be a source of awe and enjoyment in Minnesota's north woods.
Concerns about climate change impacts on moose have fueled interest in how these large-bodied animals respond to elevated ambient temperatures. Moose are adapted to survive in cold temperatures; however, increasingly warmer winters have been linked to the moose decline in northwestern Minnesota and may be playing a role in the northeast as well.
Researchers have implanted a subset of wild moose in Minnesota with special transmitters that record internal body temperature and transmit this information to their collar. This device, called a mortality implant transmitter (MIT), also is able to record heart activity and send an alert to moose responders if an animal's heart stops beating.
To better understand how moose respond to changes in ambient temperature and how the MIT data may be properly interpreted, researchers from Minnesota began a collaborative project with the Moose Research Center in Alaska in December 2014. The goal of this project is to implant captive moose with the same MITs being used in wild moose in Minnesota and then record their body temperature and behaviors to help understand how moose mitigate heat.
Minnesota mystery: What's killing the moose? (New York Times)
What's killing Minnesota's moose population? (CBS Evening News with Scott Pelley)
The high-tech detective hunt to save Minnesota's moose (America Tonight, Al-Jazeera America)
Numbers improve but Minnesota moose still not out of the woods (Minnesota Public Radio)
Moose mortality study continues, population drop still a mystery (WDIO, Duluth, ABC)
High Tech Research Targets Moose Mortality Mystery (WCCO, Minneapolis-St. Paul, CBS MN)
What's Killing Minnesota's Moose (St. Paul Pioneer Press, St. Paul, MediaNews Group)
Eyewitness News Special Report: A Desperate Measure (WDIO, Duluth, ABC)
Eyewitness News Special Report: Communities Concerned About Moose (WDIO, Duluth, ABC)
Moose hunt canceled; DNR works to answer population decline (KARE, Minneapolis-St. Paul, NBC)