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

Abstract The Interior Population of trumpeter swans ( Cygnus buccinator ) has expanded substantially since initial reintroduction efforts. Given recent trends following multiple successful releases beginning in the 1980s, we predicted continued expansion, especially into the nearby Prairie Pothole Region. To support management, we developed a landscape suitability model and range expansion estimates (2023‒2033) to help jurisdictions anticipate future swan distribution. We assessed landscape suitability for breeding trumpeter swans with a use‐available study design based on global positioning system (GPS) collar data (2019‒2023) from swans in the western Great Lakes region of the United States and Canada. We related occurrence and pseudo‐absences to landscape‐scale summaries of upland and wetland conditions in a logistic mixed‐effects model. We then incorporated landscape suitability into a range expansion model, which used logistic regression to estimate the probability of 50‐km grid cells being occupied by 2033, where time‐series citizen‐science data summaries (2004–2023) of newly occupied range cells and unoccupied cells were related to year, survey effort, landscape suitability, and distance to previously occupied cells. Landscape suitability was positively related to greater amounts of wetland perimeter and foraging areas. Range expansion was positively associated with landscape suitability and survey intensity and negatively associated with year and distance to previously occupied cells. We estimated a 4.4% (95% CI = 2.0–6.9%) annual range expansion rate from 2023 to 2033, with expansion occurring in the Prairie Pothole Region of the Dakotas and the Boreal Shield and James Bay Lowlands of Canada. Our models can support proactive conservation planning by identifying priority areas for habitat management and public outreach. Notably, North Dakota and South Dakota permit tundra swan ( Cygnus columbianus ) hunting but not trumpeter swan hunting, emphasizing the need for targeted hunter education to prevent unintended take of the similar‐looking species and support the establishment of persistent trumpeter swan populations.