Veiled Polypore (Cryptoporus volvatus) as a Foraging Substrate for the White-Headed Woodpecker (Picoides albolarvatus)

Abstract

In the northwest, White-headed Woodpeckers (Picoides albolarvatus) are an uncommon species restricted to interior, dry coniferous forests. This species forages primarily by probing in bark crevices, surface gleaning, and excavating below the bark. Here we report on an observation from Mt. Ashland in southern Oregon of a White-headed Woodpecker feeding on insects in and around the sporophores of Veiled Polypore (Cryptoporus volvatus). Inspection of other sporophores with signs of woodpecker feeding revealed abundant fly larvae and beetles (adults and larvae). This widespread decay fungus colonizes the sapwood of recently dead trees where it is frequently associated with bark beetles. A suite of other insects is attracted to the sporophore, many using the enclosed pouch as a pupation chamber. In addition to exploring the significance of C. volvatus as a foraging substrate for White-headed Woodpeckers, we discuss the potential role of White-headed Woodpeckers as dispersal agents for C. volvatus and the possible interplay between C. volvatus-induced decay, insect availability, and habitat selection by White-headed Woodpeckers.