Red fox home ranges, activity patterns, and resource selection on an Atlantic barrier island

Abstract

Relatively little is known about red fox (Vulpes vulpes) spatial ecology on barrier islands, where semi-linear habitat distribution and aquatic barriers may affect terrestrial movements. Because red foxes often are a predator of imperiled shorebirds in these ecosystems, and predation is often managed along with other factors such as habitat limitation, this information is needed to inform effective holistic management. The goals of this study were to describe red fox spatial ecology in a barrier island ecosystem and compare these findings to the existing literature on red fox space use in other coastal settings. We used global positioning system (GPS) collar data collected from 2015–2018 from 31 red foxes to estimate sizes of home ranges and core-use areas, describe daily activity patterns, and investigate within-home-range resource selection among red foxes on Fire Island, New York, USA. Twenty-two of 31 red foxes maintained distinct home ranges throughout the monitoring period, while 9 were transient, regularly traveling through the home ranges of other red foxes and among management units across the island. Observed GPS-collared red fox home range sizes (95% time local convex hull [t-LoCoH] isopleths) ranged from 10 ha to 659 ha, averaging 59 ± 7 ha (SE) among resident foxes and 447 ± 46 ha among transient foxes. Core-use areas (50% t-LoCoH isopleths) ranged from <1 ha to 268 ha, averaging 10 ± 1 ha among resident foxes and 67 ± 27 ha among transient foxes. Hourly minimum movement rates varied across the diel cycle and among individuals, averaging 216 m/hour ± 9 m/hour, and were highest 13–22 hours after sunrise. Within-home-range resource selection varied among activity periods. For example, red foxes selected areas closer than expected to vegetation based on availability during the daytime and twilight hours but farther than expected from vegetation at night. We recommend vegetation management in and around shorebird nesting areas to reduce daytime resting sites and hunting cover for red foxes while improving suitability for use by nesting shorebirds. We also suggest coordination of predator management activities across agencies in this situation and in others where predators regularly cross management unit boundaries. Overall, we found that many aspects of red fox space use in the study area, such as smaller average home ranges compared to those in other ecosystems, were similar to that of red foxes in other coastal settings; additional research is needed to determine whether this holds true in other barrier island systems.