Droning on for conservation
Sage thrasher (Photo by Dick Cannings)
Emerging technology brings new angle to conservation research in BC
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The sage thrasher has very particular requirements for its nesting habitat. It has to be a bush, ideally a big one in a kind of elliptical shape, surrounded by a patch of bare ground. The shrubs should be tall and sturdy enough to support sizable nests and thick enough to protect the birds from predators and the sun.
Sage thrashers are what is known as an obligate species, which means that they're not just picky about their living arrangements, they need these particular features in the environment in order to breed and survive.
Sagebrush at Sage and Sparrow Conservation Area (Photo by NCC)
Dr. Rhonda Millikin, head of the Habitat Assessment and Data Management unit at the Canadian Wildlife Service, Environment and Climate Change Canada, knows a great deal about the sage thrasher's nesting specifications. In the 1990s, Millikin studied sage thrasher habitat as a land bird biologist for BC and the Yukon. As chair of the Sage Thrasher Recovery Team, she was struck by the idea that if the team could just fly over the areas they suspected provided habitat for the birds, they could easily spot the right bushes.
"But at that point we didn't even have GPS," Millikin says. "There were certainly no drones."
Twenty years on, thanks to the emergence and accessibility of drone technology, Millikin and her team are heading out into the field. Finally, they have a chance to test her thesis.
Sage thrasher at Sagebrush Slopes (Photo by Andy Teucher)
Sage thrashers live in hot, dry regions, in a distribution range that spreads from New Mexico and Arizona to the very southern parts of BC, Alberta and Saskatchewan. Increasing threats to their sagebrush habitat, however, are challenging the birds right across North America.
The sage thrasher is endangered across BC. This is largely due to the destruction and degradation of sagebrush habitats through development and unsustainable grazing practices.
"A certain level of grazing is fine, and might even be helpful," Millikin clarifies. "But over-grazing is a problem."
This year, Millikin and her rented drone are mapping sage thrasher habitat in BC's southern interior, including at the Nature Conservancy of Canada's (NCC's) Sage and Sparrow Conservation Area.
By getting a scan of the area, the team can identify sagebrush bushes and locate critical habitat areas. Based on the their size, the sagebrush will be assessed as either nest or non-nest bushes. A member of the research team will then go out in the field to check whether those findings are valid: do the bushes actually contain sage thrasher nests?
Pinpointing these critical habitat areas will help the Canadian Wildlife Service as they seek to protect sage thrasher habitat. It can also suggest regions that might be hospitable for sage thrashers in the near future. With rising temperatures due to climate change, it's possible that the birds will be able to move further into the province, and the southern interior could become a haven for them as they're pushed north from the United States.
Drone used in initial study by Rhonda Millikin (Photo by Rhonda Millikin)
This isn't the first time Millikin has used an unstaffed aerial vehicle (UAV or drone) in the field. In 2015, she and her team studied how birds would respond to the technology — an important step in ensuring that using drones wouldn't disturb the birds.
Their findings: birds have no problem with drones, at least not the helicopter type, which looks less like a predator than the fixed-wing model does.
"The type we used on this trial is more like a bug," Millikin says. "It takes off straight up and kind of hovers."
As for the benefits? There are many reasons to use drones for conservation work.
"They're unbiased," Millikin says. "You could fly an area tomorrow and again in five years and see what has changed, knowing that the methodology is collecting the information in exactly the same way. When I go out and re-observe an area with just my ears and eyes — well, I find I don't hear and see quite as clear as I did in the 90s."
As well as being efficient, drones can help reduce impact on sensitive lands.
"Drones can cover a large area in a very controlled fashion," Millikin says, "So if there are landscapes we don't want to drive into, the drone can fly in for us."
Helping to reduce human impact is vital for landscapes that are already weathering the effects of human disruption.
So far the project is looking good. Next on the agenda for Millikin and her team: sorting through the reams of data acquired through the drone mapping.
Despite the many benefits that drones brings to her research, Millikin admits that "technology cannot replace the human observer. We really do need experts who can interpret the information and validate it."
And technology does offer a key opportunity for conservation teams to get ahead of the curve — get into areas quicker, assess priority habitat and make decisions to protect it — before the areas are lost.
"With so much population growth and development pressures on our landscape, we need to be really efficient and prioritize in an unbiased way," Millikin says.
At least in the case of the sage thrasher, drones might just be the thing.