Spatial ecology of a translocated, imperiled lagomorph on a newly inhabited island

Context Islands can be used to aid conservation efforts for rare species by providing a safe refuge. Over the past decade, islands have been used to aid in conserving New England cottontail (NEC; Sylvilagus transitionalis), by serving as a source for translocations to mainland release sites. The success of the first breeding colony island led to the initiation of Nomans Land Island National Wildlife Refuge (NWR) as a second island colony. Nomans Land Island NWR is 255 ha of wildlands uninhabited by people and managed by the United States Fish and Wildlife Service. The release of NEC on the island occurred from 2019 to 2021, with the translocation of 26 NEC. Aims Our objectives were to monitor the initial founding NEC released on Nomans Land Island NWR by (1) estimating their home range area, (2) determining their overlap in home ranges among individuals, and (3) assessing their fine-scale resource selection. Methods We deployed Global Positioning System radio collars on the founding NEC released in two subsequent years. We first used a continuous time movement modeling approach to estimate NEC home ranges and core-use areas. Next, we estimated NEC resource selection with a used–available framework. Environmental layers included habitat classifications and normalized difference vegetation index values derived from aerial imagery. Key results We found high amounts of variability among individuals in both their home ranges and resources selected, with individual-level resource selection often differing from population-level selection. We suspect their home ranges were initially larger than what has been estimated for mainland NEC because the island was uninhabited by rabbits prior to the release of NEC. Their average home range decreased the second year, which was likely to be a result of the increased density of NEC on the island. Conclusions The founding NEC used a wide variety of different vegetation cover types on the island, which indicates that they will likely populate the entire island. Monitoring translocated animals is key in determining their ability to establish self-sustaining populations. Implications Islands have played an integral role in NEC conservation and there are plans to increase the number of breeding colony islands. Breeding colony islands also could be used to aid in the conservation of other imperiled, small mammals.