Red-headed Woodpecker (Melanerpes erythrocephalus) winter roost-site selection in a burned forest stand

Abstract

In temperate regions, winter is characterized by high thermoregulatory demands and low food availability. For woodpeckers, winter survival depends on selecting habitat that provides both suitable roost trees and adequate food. The Red-headed Woodpecker (Melanerpes erythrocephalus) has experienced precipitous declines across much of its range in the past 50 yr, yet causes of declines remain elusive. Although previous studies have focused primarily on the breeding season, understanding winter roost-site requirements is crucial for the maintenance of Red-headed Woodpecker populations across the full annual cycle. Our study investigated winter roost-site characteristics at 3 spatial scales (roost patch, tree, and cavity) in a 41 ha fire-affected forest stand located in northern Virginia. From February to April of 2016 we tracked Red-headed Woodpeckers to 42 roost-sites during evening surveys. To determine the features driving roost-site selection, we compared vegetation surrounding the roost to random sites within the same forest stand, and occupied roost snags (standing dead trees) were compared to the closest available snag. Cavity height and orientation were also examined. We modelled roost-site selection at both the patch and tree scales using logistic regression and identified important variables and their influence by estimating regression coefficients and their model-averaged parameter weights. Habitat within the patch surrounding roost trees had higher basal area of snags and mast-producing trees compared to random sites. Red-headed Woodpeckers selected roost snags with signs of decay and showed preferences based on snag taxon. Our findings indicate that managing land that produces and retains both snags and mature mast-producing trees will benefit overwintering populations of Red-headed Woodpeckers. This study provides the first detailed analysis of winter roost-site selection in this declining species.