Conservation status assessment of the Sharp-shinned Hawk, an endangered insular raptor in Puerto Rico

Abstract

Sharp‐shinned Hawks (Accipiter striatus) are forest raptors that are widely distributed in the Americas. A subspecies endemic to Puerto Rico (A. s. venator) is listed as endangered and restricted to mature and old secondary montane forests and shade coffee plantations. However, recent information about the population status and distribution of Puerto Rican Sharp‐shinned Hawks is lacking. We developed a spatial geographic distribution model for Sharp‐shinned Hawks in Puerto Rico from 33 locations collected during four breeding seasons (2013–2016) using biologically relevant landscape variables (aspect, canopy closure, elevation, rainfall, slope, and terrain roughness). Elevation accounted for 89.8% of the model fit and predicted that the greatest probability of occurrence of Sharp‐shinned Hawks in Puerto Rico (> 60%) was at elevations above 900 m. Based on our model, an estimated 56.1 km2 of habitat exists in Puerto Rico with a high probability of occurrence. This total represents ~0.6% of the island's area. Public lands included 43.8% of habitat with high probability of occurrence (24.6 km2), 96% of which was located within four protected areas. Our results suggest that Sharp‐shinned Hawks are rare in Puerto Rico and restricted to the higher elevations of the Cordillera Central. Additional research is needed to identify and address ecological limiting factors, and recovery actions are needed to avoid the extinction of this endemic island raptor.

Towards reconciliation of the four world bird lists: hotspots of disagreement in taxonomy of raptors

“…For example, the Puerto Rican sharp-shinned hawk (Accipiter striatus venator) is critically endangered, yet currently considered a subspecies by all four world bird lists. Extinction of this subspecies would result in the loss of the only resident accipiter in Puerto Rico [51]. Despite situations where subspecies conservation is obviously warranted, there is some agreement that conservation of species generally supersedes that of subspecies (e.g.…”

Global raptor research and conservation priorities: Tropical raptors fall prey to knowledge gaps

“…This subspecies has thus been the subject of major reintroduction, management and research efforts (McClure, Pauli, Mutch, & Juergens, 2017a). The Puerto Rican Sharp-shinned hawk (Accipiter striatus venator) is another example of a subspecies being nearly extinct (Gallardo & Vilella, 2017), although the species is Least Concern. Conversely, conservation efforts for the Cape Verde Kite, previously considered by some to be a distinct species (Milvus fasciicauda;Ferguson-Lees & Christie, 2001), were virtually abandoned once it was determined to be non-monophyletic (Johnson, Watson, & Mindell, 2005).…”

The World's Most Imperiled Raptors Present Substantial Conservation Challenges

“…Recent genetic and morphological analyses suggest that this taxon should be considered a species (Catanach et al 2021). Given the rarity of the Puerto Rican Sharp-shinned Hawk and its drastic population decline due to Hurricane Maria (Gallardo and Vilella 2017), this taxon would likely be listed as critically endangered if considered a species. We therefore recommend a taxonomic reevaluation of the Puerto Rican Sharp-shinned Hawk so that this taxon can be properly prioritized for conservation action.…”