Combining band recovery data and Pollock's robust design to model temporary and permanent emigration

Area of Science:

• Ecology
• Wildlife Biology
• Statistical Modeling

Background:

• Capture-recapture models are essential for estimating demographic parameters in marked populations.
• Existing models often require multi-site sampling for dispersal estimation.
• Single-site sampling limits the ability to distinguish between temporary and permanent emigration.

Purpose of the Study:

• To develop a likelihood-based approach for simultaneously estimating temporary and permanent emigration from single-site capture-recapture data.
• To integrate robust design sampling with immediate post-sampling recovery data.
• To apply the developed model to estimate emigration probabilities in Canvasback ducks.

Main Methods:

• Utilized a capture-recapture framework combined with a robust design.
• Incorporated immediate recovery data following sampling periods.
• Developed a general likelihood-based model with a first-order Markov process for temporary emigration.

Main Results:

• Estimated the probability of permanent emigration for adult female Canvasback ducks at 0.193 (SE = 0.082).
• Demonstrated that individuals present in a previous year have a higher probability of returning in the current year.
• Successfully applied the novel model to real-world wildlife data.

Conclusions:

• The new model effectively estimates both temporary and permanent emigration using single-site data.
• Findings provide crucial insights into the dispersal patterns of Canvasback ducks.
• This approach enhances the utility of capture-recapture methods for studying open populations.