Environmental Variables and Eyrie Site Characteristics Associated with Breeding Productivity of the Barbary Falcon (Falco peregrinus pelegrinoides): Potential Implications for Release Site Evaluation.

Environmental variables and eyrie site characteristics may influence reproductive output, yet their associations with Barbary falcon (Falco peregrinus pelegrinoides) productivity remain poorly understood in the Arabian Peninsula. We quantified fledgling production at 59 monitored eyries in northwestern and southwestern Saudi Arabia during the 2026 breeding season. Poisson generalized linear models evaluated February-May climatic conditions, pair type, eyrie cliff-wind alignment (CosDiff), and elevation and eyrie height where available. Monthly analyses for February-April and COM-Poisson sensitivity models assessed temporal consistency and robustness to departures from Poisson equidispersion. Mean productivity was 1.97 fledglings per eyrie (SD = 1.25; range = 0-4). In the best ranked additive model, a one standard deviation increase in seasonal mean wind speed (0.678 m s-1) was associated with 19.5% lower expected productivity (IRR = 0.805, 95% CI = 0.660-0.982, p = 0.032), and more direct eyrie cliff alignment with incoming prevailing wind was associated with 18.7% lower expected productivity (IRR = 0.813, 95% CI = 0.677-0.976, p = 0.026). Monthly wind estimates were comparable across February-April. These findings may inform preliminary release site evaluation, but multi-year studies with cliff-scale measurements are needed to determine whether these associations persist across breeding seasons.