Foraging Patterns of Cavity-Nesting Birds in Fire-Suppressed and Prescribe-burned Ponderosa Pine Forests in Montana

Abstract

Fuel-reduction/forest restoration treatments that consist of thinning followed by prescribed burning are becoming increasingly important land management actions that likely affect various wildlife species. To assess potential effects on bark-gleaning birds, we compared the foraging patterns of five cavity-nesting species in thinned and burned ponderosa pine (Pinus ponderosa) forest sites and control sites. We recorded foraging behavior, location on forage tree, and tree characteristics that may be important in the selection of foraging substrates. Foraging surveys were conducted on three replicate 20-ha thinned/burned plots located within larger treatments that ranged from 60 - 250 ha, paired with three replicate control plots. Red-breasted Nuthatches (Sitta canadensis) foraged more often in control sites. Mountain Chickadees (Poecile gambeli) foraged at similar rates on both treatment types. Black-backed Woodpeckers (Picoides arcticus), Hairy Woodpeckers (P. villosus) and White-breasted Nuthatches (Sitta carolinensis) foraged almost exclusively in thinned/burned sites. Overall, all species selectively foraged on larger diameter trees. In control sites, Red-breasted Nuthatches selected larger ponderosa pine trees and Mountain Chickadees selected larger, live trees. In thinned/burned sites, Red-breasted Nuthatches selected larger, live trees, Mountain Chickadees selected larger trees with more canopy connections, Black-backed Woodpeckers selected trees with beetle evidence present and Hairy Woodpeckers selected recently dead trees. These results suggest fuel reduction/forest restoration treatments in dry ponderosa pine forests may be compatible with providing foraging substrates for cavity-nesting species often present in post-fire habitats.