Space-time home range estimates and resource selection for the Critically Endangered Philippine Eagle on Mindanao

Abstract

Quantifying home range size and habitat resource selection are important elements in wildlife ecology and are useful for informing conservation action. Many home range estimators and resource selection functions are currently in use. However, both methods are fraught with analytical issues inherent within autocorrelated movement data from irregular sampling and interpretation of resource selection model parameters to inform conservation management. Here, we apply satellite telemetry and remote sensing technologies to provide first estimates of home range size and resource selection for six adult Philippine Eagles (Pithecophaga jefferyi), using five home range estimators and non-parametric resource selection functions. From all home range estimators, the median 95 % home range size was between 39-68 km2 (range: 22-161 km2), with the 50 % core range size between 6-13 km2 (range: 5-33 km2). The space-time autocorrelated kernel density estimate (AKDE) had the largest median 95 % home range size = 68 km2 and a 50 % core range = 13 km2. Local convex hulls (LoCoH) estimated the smallest median 95 % home range = 39 km2 and a 50 % core range = 6 km2. From the resource selection functions, all adults used areas high in photosynthetic leaf and canopy structure but avoided areas of old growth biomass and denser areas of vegetation, possibly due to foraging forays into fragmented areas away from nesting sites. For the first time, we determine two important spatial processes for this Critically Endangered raptor that can help in directing conservation management. Rather than employing a single home range estimator, we recommend that analysts consider multiple approaches to animal movement data to fully explore space-time and resource use.