Mesocarnivore presence and behavior on a barrier island during sea turtle nesting season

Abstract

Abstract Red fox (Vulpes vulpes) management has been conducted on Masonboro Island Reserve, a component of the North Carolina National Estuarine Research Reserve, North Carolina, USA, since 2013 to reduce depredation on loggerhead sea turtle (Caretta caretta) and green sea turtle (Chelonia mydas) nests. Depredation rates have varied among years indicating either an influx of red fox onto the island post cull or other mesocarnivores preying on sea turtle nests. We investigated the presence of red fox and other mesocarnivores on Masonboro Island Reserve after a culling event in 2016 to characterize mesocarnivore behavior and interactions during the turtle nesting season. We systematically placed 17 Moultrie® panoramic 150 passive infrared cameras every 0.80\u202fkm along the base of the dunes on the shoreline of Masonboro Island Reserve during May–October 2016. Of 81,509 pictures taken by the cameras, we observed 2 red fox and 1 Virginia opossum (Didelphis virginianus). There was 1 documented mammalian depredation event on turtle nests in 2016 and the number of false crawls (where females return to the ocean without laying eggs) was lower than the previous 5 years. Given that we only recorded 3 pictures on 2 different nights of mesocarnivores, our results may indicate that the 2016 cull was successful. Mesocarnivores, especially red fox and raccoons (Procyon lotor), on the mainland may temporarily shift their home range during the onset of the turtle nesting season to procure food for their offspring. By early fall, most mammal offspring disperse and likely recolonize the island annually, suggesting management efforts to reduce mammalian predators should continue. Human and domestic dog (Canis familiaris) presence on the island is abundant and also may influence turtle nest success.