New citizen-science project aims to track important avian migratory routes in Nova Scotia

Every year in southwestern Nova Scotia, a barely perceptible series of nocturnal chirps marks the presence of an avian highway in the sky overhead. 

A citizen-driven project is now using novel technology and AI to chart these migratory routes and other important habitats in the province. 

The Listening Together project is using inexpensive audio recorders, combined with machine-learning software, to record and analyze bird calls.

Project founder John Kearney said the increasing availability of technology allows for a project that not only provides data, but also opens up greater opportunities for communities to participate directly in research.

"The technology used to be very expensive, and only a few people could afford to do it. But now, for $50 US, you can have your own complete recording unit. And so what that enables is that you can put many of these out into the field," Kearney said.

"It's not just a question of let's go out and monitor and see how biodiversity is increasing or decreasing, but also learning from each other, how we're not only going to transform ourselves, but transform our world."

Bioacoustic monitoring has a long history in Canada. In 1949, the first recordings of marine mammals — beluga whales in the Saguenay river in Quebec — prompted a major increase in whale research, and acoustic monitoring on land has been growing in popularity since the 1990s.

But the Listening Together project is taking advantage of technological developments from the last several years, which have made this kind of monitoring much more accessible.

The project focuses on two species at risk — the Canada warbler and the Leach's storm petrel. The latter is considered threatened.

Kearney said habitat conservation often focuses on breeding habitat, which only hosts a species such as the Canada warbler for part of the year.  

"It's very important that we preserve the habitat of these threatened species throughout their annual cycle. So we're looking at it in terms of what are the habitats that we need to protect so that these Canada warblers can get the nutrition they need along the road?"

AudioMoths allow for monitoring at night, when the warblers are migrating, emitting buzzes and whistles as they fly. 

For the Leach's storm petrel, where the focus is more on identifying nesting sites on remote islands, Kearney said this kind of monitoring is particularly important, to track changes in the species from the beginning of the period in which it's been designated as threatened. 

Until recently, bioacoustic monitoring of habitat was an expensive and time-consuming endeavour, requiring recorders that cost thousands of dollars and generated files that needed specialist analysis. 

For this project though, Kearney is relying on AudioMoths, an inexpensive, open-source audio recorder first created by researchers at the University of Southampton in the U.K. in 2017, to monitor for the sound of gunshots — and therefore, poaching — in nature reserves in Belize. 

The recorders, which are the size of a bar of soap, can be placed in a plastic sandwich bag to keep them dry, and hung on a tree or post, where they record sound on their own. 

Kearney said through Listening Together, community members have placed AudioMoths throughout Kespukwitk — the Mi'kmaw name for the region — for Canada warbler detection, and on two coastal islands for Leach's storm petrel. 

Tony Millard, a birder and director of the Nova Scotia Bird Society who lives in Cape Forchu, has been helping with the project. He said the recorders make it possible for citizens to be directly involved in data collection. 

"That's it, this wonderful little listening device with microchip things inside it. And then you get somebody once a month to take out the chip and have a program on your computer, plug it in, and look at the data. It's not that involved."

Some of the new programs the project is using for analysis, like BirdNet — a research project by U.S. and German universities — or Merlin Bird ID, use machine learning to identify bird calls based on recordings, allowing non-specialists to be involved in interpreting at least some of the data.

These programs can also be used to pick out bird calls from hundreds of hours of recordings (in other cases, spectrograms — a visual representation of sound frequencies — can be analyzed by a trained individual, to identify birds to the species level)

Millard said these automated approaches could be especially useful in coming years, for documenting changes in species distribution due to climate change. 

"There's so much technology in the future [that] we're going to have our birding armoury, to help us," Millard said. 

Phil Taylor, a professor in the department of biology at Acadia University who's been involved in the project and has conducted other citizen science monitoring projects — including having volunteers deploy AudioMoths across New Brunswick this past summer to monitor for migrating Black Scoters — said this kind of inexpensive bioacoustic monitoring expands both the geographical reach of research, and its reach into the general population.

"It totally changes what you can think about and what you can do," said Taylor. "And it's a way for [people] to contribute, and it engages them, and then, when you start writing things up and, and putting the analysis and the summaries out there, those people are interested."

Taylor said it's particularly important to use these tools to focus on migratory habitat, because while breeding habitat is well-documented and therefore shapes policy, migratory habitat is less understood—even though migration is often the most dangerous time for birds.

"So having a better understanding of where they go and where they stop over may help us direct some policy toward protecting habitat during migration."

'It's for everybody'

So far, the Listening Together project has identified an area in Digby County that is an important staging ground for Canada Warblers that are preparing to fly across the Bay of Fundy, and is now using support from a fund meant to establish areas for potential protection in the province, and will be conducting surveys on further areas that are habitat for migrating birds. 

In a statement, the Department of Environment said it is important that areas of high biodiversity value be identified, to guide decisions around provincial protection of land. 

Kearney hopes that going forward, participants in the project will continue to do more than collect data, since the contribution of perspectives from project partners, which include Acadia First Nation and academic institutions, as well as a growing cohort of people who've become more interested in exploring nature since the start of the pandemic, increases the potential impact of the work. 

"This desire to conserve nature goes hand in hand with understanding it, and seeing it related back to us, as interdependent with these plants and animals," said Kearney. 

"I sincerely think that if we're gonna solve this ecological crisis that we have, science alone is not going to do it, we're going to have to understand it from a cultural, spiritual and scientific point of view. And so I think that kind of understanding is not something just for scientists. It's for everybody."