Proper flight technique for using a small rotary-winged drone aircraft to safely, quickly, and accurately survey raptor nests

Abstract

Small rotary-winged unmanned aerial vehicles or “drones” mounted with a small video camera were successful in surveying the nest contents of four species of raptor, including Osprey (Pandion haliaetus), Bald Eagle (Haliaeetus leucocephalus), Ferruginous Hawk (Buteo regalis), and Red-tailed Hawk (B. jamaicensis) in an accurate and safe manner when the proper flight technique was employed. A total of 110 surveys were completed in 2013 and 2014 with quality images of nest contents obtained in 106 or (96.4%) of flights. A successful and safe flight requires two personnel: the pilot who controls the aircraft and the spotter who monitors the behaviour of the adult birds defending the nest and keeps the pilot updated on all potentially dangerous interactions between aircraft and the birds. With the video camera recording, the aircraft is flown above the nest to a predetermined location that allows an unobscured camera shot of the nest. This technique can be readily adapted to a variety of habitat types and species. The accuracy of data obtained combined with the flexibility, low cost, and speed of this technique make it a useful technological alternative to the safety risks and obtrusiveness associated with traditional survey techniques.