Waterbird nest survival derived from drone surveys

Drone surveys provide accurate estimates of nest abundance and survival for ground-nesting waterbird species, but drones have not been used to estimate survival for waterbirds nesting in a canopied swamp habitat. We compared nest survival of Snowy Egret (Egretta thula), Great Egret (Ardea alba), Tricolored Heron (Egretta tricolor), Glossy Ibis (Plegadis falcinellus), and Cattle Egret (Ardea ibis) between traditional ground surveys and drone survey methods in freshwater wetland habitats of Florida, USA, in 2021. Overall, there were minimal differences in survival estimates between methods. However, drone-derived estimates of dark-colored waterbirds had lower accuracy than drone-derived estimates of white-colored waterbirds. Our results suggest that drone surveys provide comparable estimates to traditional ground-based methods for nest survival of waterbirds breeding in swamp habitat, and they offer the advantage of causing less disturbance to birds than traditional methods if flown at appropriate altitudes and following best practices.