Native parasitic nest fly impacts reproductive success of an island‐endemic host

Abstract

AbstractParasitic nest flies Philornis spp. are a driving force threatening the extinction of bird species endemic to Neotropical islands such as the Galápagos, where introduced Philornis downsi negatively impacts reproductive success of naïve avian hosts. Elsewhere in the Neotropics, such as in the Caribbean region where Philornis nest flies are native, effects of Philornis on host productivity are poorly known. We manipulated parasitism by the native Hispaniolan nest fly Philornis pici on a critically endangered endemic host, Ridgway's hawk Buteo ridgwayi, to study the impact of nest fly myiasis on hawk breeding success with the goal of providing a management option for endangered species until broad‐scale solutions can be found. Our treatment protocol was enough to reduce P. pici abundance by 89% and increase probability of fledging by 179% for treated nestlings. Our results indicate that parasitism by nest flies decreases survival and fledging success of nestling Ridgway's hawks and is a possible factor in the decline of the species. To the best of our knowledge, this work represents the first quantitative evidence of nest fly impact on survival or productivity in a non‐passerine host.