Landscape suitability and range expansion estimates for the North American Interior Population of trumpeter swans

By Kevin W. Barnes, Thomas R. Cooper, David E. Andersen, Mike E. Estey and David W. Wolfson

Trumpeter swans (Cygnus buccinator) are making a remarkable comeback. Once pushed to the brink of extinction in much of North America, the Interior Population has grown steadily since reintroduction efforts began in the 1980s.

Today, this population is secure and actively expanding into new areas. Our recent research set out to understand where these swans are most likely to establish new breeding populations in the coming decade and what factors influence their range expansion.

Cygnus buccinator (trumpeter swans). Image by WWT

To answer these questions, we combined modern tracking technology, satellite imagery, and citizen science observations. Using GPS collar data collected from trumpeter swans in the western Great Lakes region between 2019 and 2023, we examined the types of landscapes where swans choose to breed. By linking swan locations with wetland and upland features derived from Sentinel-2 satellite imagery, we were able to identify habitat characteristics that best support nesting and foraging. These included wetland-rich landscapes with extensive shoreline and good access to foraging areas.

To predict where trumpeter swans are most likely to move next, we used two decades of citizen science records to track the colonisation of new areas. Our models revealed that swans are more likely to establish in places with high habitat suitability close to existing populations. Based on these findings, we estimate that the Interior Population will expand its breeding range at a rate of about 4.4% per year from 2023 to 2033 into areas like the Prairie Pothole Region of North and South Dakota, USA, along with parts of the Boreal Shield and James Bay Lowlands of Canada.

Regional-scale and Local-scale planning

For managers, these projections highlight regional- and local-scale priority areas for habitat conservation, monitoring, and public outreach. This is especially important because both North Dakota and South Dakota allow hunting of tundra swans (Cygnus columbianus), which closely resemble trumpeter swans. As trumpeters colonize these landscapes, targeted hunter education will be essential to avoid accidental take and support the establishment of persistent new populations.

Our study shows how combining satellite data, tracking technology, and community science can provide powerful insights into species recovery and future range dynamics. As trumpeter swans reclaim their historic landscapes, we can anticipate where they will go next and ensure that their conservation success story continues to unfold.

Please see links to the full article, or associated data downloads and webmap for more information.

Article – https://wildlife.onlinelibrary.wiley.com/doi/10.1002/jwmg.70077

Data download – https://iris.fws.gov/APPS/ServCat/Reference/Profile/179264

Webmap – https://ee-kevinbarnes.projects.earthengine.app/view/trumpeter-swan-model-explorer