Influence of pre-fire beetle kill on post-fire hairy woodpecker (Leuconotopicus villosus) abundance in the Southern Rocky Mountains, Colorado

Abstract

Increasing wildfire frequency and severity in the western United States, combined with widespread bark beetle outbreaks, have significantly altered forest ecosystems in the Rocky Mountains. These interacting disturbances are reshaping post-fire habitats, particularly for cavity-nesting birds such as the Hairy Woodpecker (Leuconotopicus villosus). This study aimed to assess how proximity to beetle-killed forest stands influenced Hairy Woodpecker relative abundance following the 2020 Cameron Peak Fire in the Southern Rocky Mountains, Colorado. We deployed automated recording units (ARUs) at 19 sites within and around the burn perimeter during summer 2023. Recordings of bird calls were analyzed using acoustic identification software to quantify woodpecker detection. Distances to beetle-killed areas were calculated using U.S. Forest Service data and geospatial analysis. A linear regression model revealed a significant negative relationship between woodpecker abundance and distance to beetle-killed forest stands (p < 0.01), with closer proximity associated with higher abundance. These results provide valuable insight into habitat selection by cavity-nesting woodpeckers, demonstrating how forest structure shaped by beetle activity can influence post-fire wildlife use. As climate change drives more frequent and intense disturbances, it is important that forest management strategies account for the lasting impacts of compound events like beetle outbreaks and wildfire to promote wildlife resilience.