CONCORD, N.H. (AP) -- Researchers studying New Hampshire's declining moose population say some of the animals being tracked are thinner than they should be for this time of year.
The New Hampshire Fish and Game Department, in partnership with the University of New Hampshire, is in the first year of a three-year study into the causes of moose mortality and how changing weather patterns may be affecting the animals. It recently hired a helicopter wildlife crew to net 43 moose, place tracking collars on them and collect fur, blood and tick samples.
Researchers will use those samples and the tracking data to evaluate the animals' immune systems and investigate whether winter ticks are the main factor in the declining population or whether there are other causes. That analysis is just starting, but biologist Kristine Rines said Monday that about 20 percent of the moose were thinner than they should be and were carrying winter tick loads that appeared heavy.
In an average year, a moose might carry about 30,000 ticks, but in a severe year, that number can be five times higher, Rines said. Unlike deer, moose are not big on grooming and have trouble shedding the ticks. Instead, they end up constantly scratching, which depletes their fur and leaves them susceptible to hypothermia, she said.
"They have a reduced immune response, so there are a lot of secondary infections that can drag them down," Rines said. "As a result, in April, when you have a bad tick year, you have a lot of mortality. These animals literally just drop dead."
If there's snow on the ground when the ticks naturally drop off the moose in April, the ticks die without reproducing, she said. But shorter winters have boosted their numbers. The department also has collected ticks from moose killed during the fall hunting season and have been troubled by those findings, she said.
"Typically, you only see larval ticks on moose in the fall, but we're starting to see adult winter ticks get on them, which is very unusual and suggests to us they may actually be able to cycle quicker than unfortunately we had hoped," she said.