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Moose herd down

Fish and Game Department waterfowl project leader Ed Robinson combed through the bristly hairs seeking winter tick on a 575-pound cow moose killed on Thursday morning in Jericho Mtn. State Park in Berlin while F & G regional wildlife biologist Will Staats recorded his findings, section by section, at the York Pond moose weigh station in Berlin. Photo by Edith Tucker. (click for larger version)
October 31, 2012
BERLIN — State Fish and Game Department wildlife biologist Kris Rines, who heads up the moose project, is once again in charge of the weigh-and-check-in station at the York Pond Fish Hatchery. She has been the state's moose project leader since 1985, a total of 27 years, which gives her a long-range perspective on the herd.

The herd has dropped to about 5,000 from about 7,000 a few years ago, she said in an informal Thursday morning interview.

This year only 275 moose hunt permits were randomly selected from a pool of 13,400 would-be moose hunters who entered the 2012 lottery. Last year 364 permits were issued. A handful of other special permits were also issued.

The number of permits issued is down, partly because the size of the herd is about where the Department's Big Game Project planning committee wanted it to reduce moose-vehicle collisions.

Once the state reached its objective of a smaller herd, fewer permits were issued, Rines explained.

Large numbers of winter ticks, spurred by warmer winters, are being also credited with killing more moose by engorging themselves and depleting their host's blood supply.

"Increased mortality can be blamed on winter ticks," Rines said. "Shorter winters result in more parasites. Complicating this, however, is that as moose density drops, the number of ticks also drops.

The presence of winter ticks on dead moose at this weigh station was carefully tallied this years by two biologists: one who combed through the moose hair in specific body locations; another who recorded the results.

Furthermore, warmer winters with higher than normal temperatures also appear to adversely affect the immune systems of moose.

Lowered immune systems, along with parasites, appear to be factors in the sharp drop in moose population in northeastern Minnesota where the moose population fell to half its size in only a few years, Rines said. "We're talking to biologists in other states all the time," she said.

"In addition, some moose cows become so debilitated by ticks in late spring — are so physiologically stressed — that they don't gain enough weight to ovulate. There is a very specific weight that cows must weight to ovulate in the fall when they reach maturity: 440 pounds for a single egg; and 550 pounds for two, potentially resulting in twins.

"Fewer eggs ovulated means fewer calves," Rines continued, pointing out that that is why successful moose hunters are required to bring in the ovaries of any cow moose they kill. "That's why we send hunters back to where they field-dressed their moose," explained Rines, adding that ovulation data is vital to understanding the health of the herd.

Still, she said, we rely on the annual deer hunter mail surveys in which we collect data on how many moose are seen in 100 hours of deer hunting. "This is the most accurate population data; the moose hunt success rate is not a reliable indicator," Rines said. Temperatures and moose hunter perseverance affect moose hunt success rates.

By nightfall on Wednesday the Department had tallied a total of 141 moose — 84 bulls and 57 cows — that had been shot in the state's 2012 moose hunt, meaning that half of the 281 hunters holding moose permits had succeeded by the midway point in the nine-day season.

Martin Lord Osman
Town of Brookfield
Town of Brookfield
Varney Smith
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