Tree characteristics selected by woodpeckers for foraging on snags and declining trees in regenerating Acadian Forest in New Brunswick

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University of New Brunswick


The value of dead and decaying wood to woodpeckers as breeding substrates is well understood. Many authors have emphasized its positive influence on woodpecker population density. However, many forest management activities including clearcuts, shelterwood cuts and seed tree cuts that result in dense, old stands with reduced snag densities are thought to negatively impact woodpecker populations. Therefore, I conducted a study on the selection of tree-scale characteristics of snags and declining trees for foraging by woodpeckers in regenerating Acadian Forest in New Brunswick to improve knowledge of the foraging habitat requirements of local woodpeckers. I searched for signs of foraging (excavation holes) by woodpeckers on 129 snags and declining trees sampled in 10 linear transects across a section of the University of New Brunswick (UNB) Woodlot. I developed a negative binomial regression model based on the presence or absence of foraging signs. I tested several variables for their influence on the probability of tree choice by woodpeckers for foraging including tree species, diameter at breast height (dbh), fungus coverage, and decay stage. Results showed that woodpeckers selected significantly larger diameter trees for excavation foraging (z = 3.197, p = 0.001, β = 0.085). Therefore, retaining large-tree and old-growth forests on site after management operations is essential to the conservation of woodpeckers in New Brunswick.