Deep in forests along the Fundy coast, 16 small recording units have spent hours each day listening to what is happening around them.
Wind and rain make it onto the recordings, along with birds at the height of their breeding season and sometimes the sounds of other wildlife moving through the forest. Researchers with the Fundy Biosphere Region are listening for one bird in particular: the Bicknell’s Thrush.
The threatened songbird has been detected along the Fundy coastline in the past, but the region remains a gap in what researchers know about its presence in New Brunswick. Fundy Biosphere’s new Fundy Thrush Watch project is trying to learn more.
“So I had learned that there were potential sightings through time of Bicknell’s Thrush on the Fundy coastline, and not a lot of work has been done about it,” said Jenna Cowie, conservation project manager with the Fundy Biosphere Region.
“So we sort of have the question of, are they there? What habitat are they using, and can they be found?”
For Cowie, the project also has a personal connection. She loves birds and has worked with Bicknell’s Thrush before.
Fundy Biosphere looks for gaps in conservation work across the upper Bay of Fundy watershed, she said, and this was one of them.
Birds Canada already has an extensive Bicknell’s Thrush monitoring program but much of that work has taken place in northern New Brunswick. Fundy Biosphere, meanwhile, has partners and connections throughout the Fundy region.
“All the pieces just sort of fell into place,” Cowie said.
Bicknell’s Thrush can be particularly difficult to study.
Amy-Lee Kouwenberg, associate director of Atlantic programs with Birds Canada, described it as a secretive bird that lives in dense forest. Researchers are much more likely to hear one than see one.
Fundy Thrush Watch deployed 16 autonomous recording units, or ARUs, at sites chosen using information from Birds Canada, Environment and Climate Change Canada and historical research. Each unit was programmed to record for two hours before sunrise and two hours after, along with an hour and a half before and after sunset.
That works out to seven hours of forest sound every day.
Cowie said the recordings contain much more than the species researchers are searching for.
“You get these windy days and these soft, rainy days and, you know, sometimes you even hear wildlife moving around,” she said.
The recordings can also be archived, allowing researchers to return to them later and look for other species recorded in the area.
Before any of that sound could be collected, the equipment had to be carried into the forest.
Cowie described deploying the units as “super, super tricky.” The terrain is remote, and some of the habitat the team wanted to reach is steep and extremely dense. They relied on maps, GPS and knowledge from people familiar with the area as they travelled through places with little or no cell service.
At some points, Cowie said, they were “pretty much on our hands and knees” trying to get over hills and around trees to reach the habitat they were looking for.
The dense growth was part of the reason they were there. Bicknell’s Thrush favours thick forest, which also makes the species difficult for researchers to find and study.
Birds Canada has monitored Bicknell’s Thrush in the Maritimes through its Mountain Birdwatch program since 2002. Kouwenberg said that monitoring has shown the population declining in the region, with declines also recorded through similar work in the United States.
Finding out whether the bird is present at a particular site can be difficult. Kouwenberg said a traditional survey can involve a trained technician standing at a point and listening for birds for about 10 minutes.
An acoustic recorder can listen for days.
“With the acoustic recorders, we can go out to places that, you know, we don’t normally go, and have it up for six days or more,” Kouwenberg said.
The devices have two microphones and are strapped to trees, with the recordings stored on SD cards.
Kouwenberg pointed to previous Birds Canada work in Cape Breton as an example of what the extra listening time can reveal. Researchers had stopped hearing Bicknell’s Thrush during traditional surveys at some locations where the birds had previously been detected. They did not know whether the birds were gone or simply weren’t being heard during the short surveys. Researchers put out acoustic recorders and detected them.
“We found they are still here,” Kouwenberg said. “It’s just you have to spend many minutes listening before you hear them.”
The finding did not erase concerns about declining numbers, but it showed the difficulty of determining whether a secretive bird is absent based on a short listening period.
The Fundy project brought back about 430 gigabytes of recordings from its 16 units.
Rather than listening to every recording from beginning to end, Cowie said the team is using software called Call Seeker to identify possible detections. Researchers then have to review those results.
The software can pull out potential thrush calls and assign them a confidence rating. A sound flagged by the program is not the same as a confirmed Bicknell’s Thrush detection, and Cowie said validation will take time.
That work was still underway when Cowie spoke with CHMA, meaning the project did not yet have an answer to the question that prompted the survey.
A 2023 draft provincial recovery plan identified recovery and survival habitat for Bicknell’s Thrush. Cowie said a small patch of survival habitat identified in that plan exists in the region where the project is working.
Her question for this year’s survey is deliberately simple.
“Are Bicknell’s Thrush using/in that survival habitat?” Cowie said. “It’s a super high-level question. Like, are they there? Are they not there?”
She cautioned that this first survey may not be conclusive enough to answer that question on its own. Instead, she described the work as preliminary and said it could lead to more detailed research.
If Bicknell’s Thrush are detected, future studies could look at the habitat they’re using, when they’re there and how many might be present.
Birds Canada is also waiting to see what the Fundy work finds.
“We’re very excited about this project that they’re doing in the Fundy region because it’s an area that we have actually not looked,” Kouwenberg said. “We just haven’t had the capacity to deploy ARUs and go looking in this area.”
There have been historical detections in the region, but Kouwenberg described it as an unknown in the organization’s current understanding of the species.
“It’ll add to the full picture of Bicknell’s Thrush in New Brunswick.”
Researchers are trying to answer those questions about a species already facing pressure on its habitat.
Kouwenberg said about 95 per cent of Bicknell’s Thrush habitat in New Brunswick overlaps with active forestry activity. But the relationship between the bird and forestry is complicated.
About eight to 10 years after a clearcut, she said, regrowth can create the dense habitat Bicknell’s Thrush favours. That is also around the stage when forests have traditionally undergone pre-commercial thinning, which can make the habitat unsuitable again for at least another decade.
Birds Canada has worked with forestry companies and provincial governments to avoid thinning in important Bicknell’s Thrush habitat.
The pressures do not stop when the birds leave New Brunswick. Kouwenberg said Bicknell’s Thrush spends its non-breeding season primarily on Hispaniola, which includes Haiti and the Dominican Republic, where habitat loss is also a concern.
Researchers are less certain about where the birds stop during migration. Kouwenberg said climate change and changes to high-elevation forests could also affect the species.
For Cowie, learning where Bicknell’s Thrush can be found is one step toward understanding what the species needs.
“They’re a really unique species. They’re a habitat specialist, so they really don’t occur everywhere,” she said. “And, you know, we should take pride that we have forests and environment that can support species like this.”
Fundy Biosphere is also producing a short film about Fundy Thrush Watch. Cowie said the project has relied on support and collaboration from organizations and people across the region.
“Everybody really wants answers on this,” she said. “They wanna see this kind of work move forward, and they want to find the answers.”
For now, those answers may be somewhere inside hundreds of gigabytes of sound recorded in the Fundy forest.
Researchers are still listening.
Theodore Ramharack holds a Bachelor of Arts in Political Science from Western University and a diploma in Broadcast Journalism. He recently completed an internship with CBC News’ The National.
Originally from Ontario, he moved to Sackville to join CHMA as a local journalist and is excited to get to know the Tantramar region and share stories from the community.
