Zigzagging in an airplane over forests and rivers, Thomas Millette scanned the Nova Scotia landscape using special thermal-imaging equipment in search of one thing: the endangered mainland moose.

The Massachusetts scientist had been directed by officials with the Department of Lands and Forestry to the most promising areas of the province to find the animal. But the searches turned up very few.

In one 592-square-kilometre section south of Halifax, just one moose was spotted. None were seen in the Liscomb Game Sanctuary, a conservation area in eastern Nova Scotia. Three were counted in two areas totalling more than 550 square kilometres in Guysborough County.

"It is clear that moose populations on the mainland are very low," Randy Milton, a manager of wildlife resources with the department, wrote in an email to Millette after reviewing the data.

The surveys, conducted in the winters of 2017 and 2018 for the provincial government, conclude the mainland moose population is in steep decline. This summer, a team of scientists will begin to put together a "status report," and will ultimately determine what, if anything, should be done to save the animal.

In the early 1900s thousands of mainland moose roamed Nova Scotia. By the 1930s there were only around 3,200 left, a number that fell to 1,000 by the early 2000s. Now, according to one of Millette's estimates, there could be fewer than 100 mainland moose remaining in the wild.

The mainland moose was declared an endangered species in Nova Scotia in 2003. (Department of Natural Resources)

The mainland moose, which was listed as endangered in 2003 and is also known as Alces alces americana, is native to Nova Scotia. They are a different subspecies from the moose on Cape Breton Island, which were introduced from Alberta in the 1940s and are far more abundant.

The results of the aerial surveys are among 535 pages of records released to CBC through a freedom-of-information request.

Lands and Forestry staff note as part of the 2017 survey a series of "drivers" that could be contributing to the decline in the mainland moose. They include climate change, changes in the forest, problems with access to good food, land management practices, road development and poaching.

Millette's work was in response to a 2016 report by Nova Scotia's auditor general that concluded Lands and Forestry was not doing enough to protect endangered species, and called on the department to reassess the population status of the mainland moose, as required under the province's Endangered Species Act.

Millette, who hails from Mount Holyoke College in Massachusetts, is a global expert in designing instruments to count wildlife from the air. He specializes in collecting aerial data to estimate animal population numbers, and his projects have included censuses for moose in Vermont and caribou in Alaska.

After Millette's second Nova Scotia survey, he wrote: "It is safe to say that if you were to double or triple the moose density set forth in this survey, there remains a paucity of moose on the mainland."

Nova Scotia banned the hunting of mainland moose in the 1930s. (Submitted by Bob Bancroft)

As part of his work in Nova Scotia, Millette used a combination of thermal imaging and high resolution photography. Several images a second were taken from a plane and then analyzed for any moose along each flight path, called transects.

From his moose counts Millette was able to calculate the moose population density for each area, and from there he estimated the population density. As part of his 2017 summary report, he estimated there could be as few as 85 moose on the mainland.

But even though Millette was hired to estimate moose presence, he said in an interview it would be a mistake to use his data to estimate the moose population because he only surveyed small areas of the province.

"The basic problem is that we know that no organism is homogeneously scattered across the landscape," he said. "That's what makes the census things so tricky ... It's a very small bit of data. That it would be a mistake to interpret that as being the densities across the province, because it was never intended to be that."

Milton agrees. Although he recognizes the moose population is "extremely low in the surveyed areas," and overall moose numbers have decreased since the last time the population was known, Milton insists the province doesn't know "how far down those numbers have actually gone."

He said it's better to use Millette's numbers to help figure out where the moose are on the mainland, and not try to estimate the population.

"Don't want to be premature and saying that numbers are so, so low that we have no hope," he said in an interview. "We want to be able to provide a good estimate on what the numbers actually are, rather than a guess."

This summer, the province will work with Millette to better understand where the moose are in the province, and how to protect those areas. A team of scientists will examine whether it's feasible to make a "recovery plan," which would aim to save the mainland moose from becoming extinct in Nova Scotia.

Millett's 2017 report includes a section entitled Questions. But the 16 pages that follow are entirely redacted under a section of the Freedom of Information and Protection of Privacy Act that says information can be hidden from public view if it's considered "advice to public body or minister."

It's unclear what information about moose could be so secretive.

Karen Beazley, a professor at the School for Resource and Environmental Studies at Dalhousie University, would like to know. Fifteen years ago she was part of a team that assessed moose habitat and population viability in Nova Scotia.

"I think that moose are sort of a canary in a coal mine," said Beazley, who reviewed the documents obtained by CBC. "If we can do some things to help the moose, that's going to help many, many other species that will suffer the same declines if we continue with the same kind of habitat loss and fragmentation that we've been doing so far."

In fact, she said what's left can't be described as moose "populations" anymore. They are just "localized remnant groups," she said, or what remains of what once was a vibrant population.

In October 2014, the remains of a poached moose were found in the woods off Highway 101 near Mount Uniacke, N.S. The meat had been removed and the hide and head left behind. (Department of Natural Resources)

Using a scientific model, Beazley said in order for moose to have a good chance of surviving over the next 100 years in mainland Nova Scotia the population would need to be somewhere between 185 and 370 animals.

The individuals in the population would have to be able to interact with one another, and not be isolated as they are today. In those geographically isolated groups, there would need to be 185 to 370 per group in order for each population to be healthy.

Beazley admits the current status is a long way from those numbers, but she's not ready to give up on the moose, stressing it is possible for species to recover from the brink of extinction.

She said it would help the moose survive if the remnant groups could get from one region of the province to another, and not be isolated from other moose groups because of highways or roads.

The other thing that would help, Beazley said, would be to decrease the number of forest roads, which open up moose areas to poachers, coyotes and deer. Deer carry a brain worm parasite that kills moose.

Millette's surveys also identified deer, and he had expected to find them in large numbers where there weren't many moose. It was a surprise that only three deer were counted in the Liscomb Game Sanctuary. Milton later noted it appears there are large areas of the mainland with almost no deer or moose "evident at all."

Beazley expects some people will claim that moose have no future in Nova Scotia because the province will become too warm due to climate change. She doesn't buy that argument.

"Historically, they have existed much further south than Nova Scotia," she said. "Nova Scotia will have a lot of sites that will be resilient to climate change … so climate change isn't necessarily going to make this area unfit for moose to survive."

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