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Friday
Jan242014

Maine Moose: How are they doing?

By Joe Rankin

Forests for Maine’s Future writer

Most visitors to Maine probably have a list of things they want to do and see. They want to go to the coast. They want to eat lobster. And they would like to see a moose.

Moose are the iconic Maine animal. One that epitomizes the mythos of the “Maine woods.” It’s Maine's official state animal and is on the state seal, for instance. You don’t see lobsters there, or bears, or deer. 

And Maine is moose country. The state has the largest population of moose in the lower 48 states, an Alces alces in his natural element (Photo: The Rankin File)estimated 65,000 to 75,000 of them. Biologists these days have a better handle on Maine’s moose numbers and ongoing and new research projects are likely to shed light on how the animal interacts with its environment and how it deals with the parasites that afflict it.

The moose is the largest member of the deer family. It is found in northern forests around the globe, across Canada and the northern United States, in northern Russia and China, Scandinavia and even Poland. 

The moose is one of those creatures that looks like it was designed by a committee:  big ears, huge nose, stilt-like legs, massive spatulate antlers. It may look awkward and gangly, but the moose is superbly designed by evolution for its environment. Those long legs carry it through deep snow with ease and it shrugs off cold winters.

There are eight subspecies of moose, four of them found in North America. The one in Maine is known as Alces alces americana, or the eastern moose. It ranges from western Ontario and the upper midwest to the Maritimes. It’s smaller than the moose found in Alaska, say, or Siberia. But it’s big enough. A good sized bull can easily weigh over half a ton, stand six feet at the shoulder and stretch nine feet from nose to tail. And they can move -- fast.

New England has always been moose country, at least since the ice sheets pulled out some 12,000 years ago. Moose are at home in spruce-fir forests and mixed woods. They browse leaves, twigs and bark of hardwoodsAn impressive adult moose (Photo courtesy Pam Wells)and certain softwoods and also eat aquatic plants.   It’s always an impressive sight to watch a big moose, submerged shoulder-deep in a fir-fringed pond, pull its head up, spraying water everywhere, and stand munching on water plants. 

Moose were apparently always plentiful in Maine. But once European settlers moved in their numbers started to decline, a result of hunting and habitat loss as forests were felled for farms. The species apparently reached a low point in the early twentieth century when only about 2,000 animals remained. Since then Maine moose numbers have rebounded, thanks to a decades-long ban on hunting during the last century, the reversion of farms to forests, and in the 1970s a spruce budworm epidemic that killed millions of acres of spruce and fir trees across the northern tier of Maine. Timber and paper companies salvaged the dying trees and within a few years regrowth began. The regenerating clearcuts became a vast moose smorgasbord. With no major predators, other than people, and a lot to eat, moose came back strong.  

“We’re fortunate in our state because the commercial forests encompass a huge amount of land that provides the most important thing moose need, which is food,“ said Lee Kantar, the moose biologist with the Maine Department of Inland Fisheries and Wildlife. 

The clearcuts created by salvage logging of budworm killed trees have pretty much grown up since the epidemic faded in the 1980s. And new forestry regulations have greatly limited clearcutting, but that doesn’t mean that moose are going to go hungry.

“It’s almost a nuanced change. We may not have the massive clearcuts, but we have a tremendous amount of timber harvesting in partial cuts on a larger footprint than before. So the amount of wood that’s removed is still tremendous and there’s a huge amount of turnover in the forest creating young forests over time.”

Calf moose. (Photo courtesy Pam Wells)Maine’s moose appear healthy. Studies of animals killed during the state’s annual fall moose hunt don’t show any drop in body size or condition. An analysis of nearly three decades of biological data showed no changes in size, said Kantar: “We still have robust animals out there, despite the changes that have occurred in the landscape.”

These days biologists have a more accurate idea of how many moose there are in Maine thanks to what Kantar describes as a “very structured” program of aerial sampling over the last few years.

The count is done using low-level helicopter flights. A pilot flies seven 25-mile long transects within a 100-square mile block of a particular wildlife management district. A separate aerial “compositional survey” of a minimum of 100 moose determines how many are bulls, cows and calves. Kantar said the two surveys have been done in each of 10 of the 12 state wildlife management areas that make up the moose core range in northern Maine. Many of the districts have been surveyed more than once. 

While Maine moose appear to be doing well, the same can’t be said of the animal all across its North American range. 

Minnesota, for instance, has seen a steep and perplexing decline in the numbers of moose. In New Hampshire scientists are seeing a “reproductive decline,” said Peter Pekins, a professor of wildlife ecology at the University of New Hampshire who has studied moose in Maine, New Hampshire and other states. Pekins said New Hampshire’s moose are likely seeing the “insidious impact” of a parasite known as the winter tick.

Several parasites prey on moose. There is brainworm, which primarily infects white-tailed deer but also infects moose where the two species overlap. There is a lungworm. There are liver flukes. Then there is the winter tick, Dermacentor albipictus.

Winter ticks parasitize moose, but also elk, deer, and caribou. They are a one-host parasite, meaning they don’t need an intermediate host to complete their life cycle. After  sucking the blood of a moose over the winter, the engorged female winter ticks drop off in the spring and lay their eggs in the forest duff. In the fall the larvae, only as big as a grain of sand, climb onto nearby foliage and wait for a suitable host to come by.

Waiting in ambush: a larval clump of winter ticks. (Photo courtesy William Samuel)“The larvae climb by the hundreds onto vegetation. When the moose walks by, just one of them has to grab onto the moose and the whole pile of them get on,” said Pekins. The larvae then attach to the moose, begin sucking its blood, and the cycle completes itself.

Moose have been found with tens of thousands of ticks on them. That many blood-sucking parasites can weaken even a big animal. Moose calves are especially vulnerable, said Pekins. “Calves just die of acute anemia. They lose too much blood,” he said. If female calves don’t die from a severe tick load it may cause them to sexually mature later, which affects the overall population. Pekins said on a heavily infested moose the engorged ticks can look like bunches of grapes. A moose with a huge number of ticks tends to lose its hair and it gets thin. They are known as “ghost moose.”

William Samuel, a professor emeritus in the Department of Biological Sciences at the University of Alberta, is author of the book “White as a Ghost: Winter Ticks and Moose” published in 2004 by the Federation of Alberta Naturalists.

Moose react to ticks the way that humans do to a great number of mosquito bites, Samuel said in an email interview. The feeding nymphs and adults cause “a severe itch sensation” that prompts the moose to rub on vegetation and groom themselves using their hind hooves and tongue, he said. All that work trying to scratch that never-ending itch can cause their winter coats to fall out prematurely, leaving them vulnerable to hypothermia.

“Moose can spend several hours each day in late winter grooming ticks. This robs them from time they should be resting and feeding,” Samuel said. High tick numbers (some moose can host more than 40,000), perhaps combined with a severe winter or a lack of enough browse, can prove fatal, though some “ghost moose” do survive, said Samuel. 

Engorged winter ticks on a moose (Photo courtesy William Samuel)Many parasites seem to be influenced by the weather. Earlier, longer and colder winters reduce parasite numbers. If winter tick females drop off a moose onto snow, their chances for laying eggs are reduced, said Pekins. Similarly, if winter arrives early, the larvae are likely to die before they can ambush a moose host. 

The big question is how climate change, which portends shorter, milder winters and warmer, wetter summers for the northeast will affect tick numbers -- and thus moose health and population -- across the region. Warmer, wetter weather favors the proliferation of slugs and snails, which serve as an intermediate host for the brainworm.

“We believe in New Hampshire that the winter tick is the number one influence on the population. It’s not easy to take that right across the border to Maine, because northern New Hampshire is basically central Maine. Conditions in northern Maine might offer more protection against this parasite,” said Pekins.

Winter tick is present across most of the moose’s North American range, including Maine. How much influence winter tick has had on Maine’s moose population is difficult to pin down, said Kantar, the Maine Department of Inland Fisheries and Wildlife’s moose specialist.

“It’s very hard to quantify geographically or even locally. How do you determine that there’s been a significant loss in that year’s cohort of calves?” Kantar asked. “There’s no question that we get overwintering calves that get to March and April with winter tick loads and end up dying from the parasite. But how many of those are out there? We don’t know.” 

While winter tick has been studied a lot, more research is needed, Pekins said, adding that projects in New Ghost moose (Photo courtesy William Samuel)Hampshire will include measuring tick loads and hair loss. Plus, New Hampshire and Maine this spring are beginning multi-year sister studies on moose mortality and productivity.

That project will entail radio collaring 30 cows and 30 calves in Maine and 20 cows and 20 calves in New Hampshire each year for two years, then monitoring those animals over five years. Most of the collars will be GPS enabled. They will send out an alert when the animal dies so it can be found and examined for parasites and diseases and to assess its age and overall condition. 

“We’re hoping that within 24 to 48 hours we are able to get on these moose and get a pretty good sense of what happened to that animal and take samples,” Kantar said. 

Pekins said that in New Hampshire researchers will supplement the electronic tracking with on-ground fieldwork, tracking down cows three times a week in certain seasons to visually check on their condition and the condition of their calves. That’s easier to do in New Hampshire, much more difficult in northern Maine, Graphic courtesy of William Samuelwhere roads are fewer, he notes.

“These projects are aimed at better understanding why something dies,” said Pekins. “For Maine this is really such a novel, novel approach. And it’s exciting because their sample size is high. It’ll probably be the second biggest project in North America at the end of two years. And we’re going to learn a lot.”

This might be the golden age of moose research in Maine.

“i feel that we’re doing a tremendous amount of work on moose. Maybe more than ever,” said Kantar. “ Between the aerial survey work, the survival work we’re embarking on, the disease work we’ve been partnering with the University of Maine Animal Health Laboratory on, the work we’ve done with the University of New Hampshire, a lot is going on. It’s exciting and it’s the type of thing we should be doing to manage such an iconic species for the people of the state.”

It’s in the management -- the number of moose hunting permits the state makes available each year and in which areas of the state -- that wildlife managers can have the most impact on the moose population as a whole. In fact, it might be the only impact, considering that they can’t control the climate, the prevalence of brainworm or the number of winter ticks. 

It’s amazing, when you think about it, said Pekins: a huge animal like the moose surges back from the brink of extinction in northern New England, even expands its range into Massachusetts, Connecticut and Rhode Island.

“We’ve enjoyed 30 years of watching an incredible story unfold and now it’s a new chapter because it can’t go on forever. We’ve been spoiled but now it has to stabilize. and it’s not stabilizing in a stable environment,” given the changing climate, said Pekins. 

Joe Rankin writes forestry articles. He lives in central Maine.