Urban woodpecker nest site characteristics before and after a hurricane disturbance

Abstract

The holes that woodpeckers excavate and use for nesting are important for many other cavity-nesting birds. The availability of appropriate substrate for cavity excavation in an urban environment is an important factor governing the abundance of woodpecker nest cavities. To understand the impacts of hurricane disturbance on characteristics of trees used by cavity-nesting birds, we surveyed woodpecker cavities in urban southeast Florida before and after Hurricane Irma in 2017. We used these data to understand which cavities were most likely to persist after the hurricane, and compare cavity tree characteristics before and after the storm. Woodpecker cavities in dead slash pine (Pinus elliottii var. densa) trees (snags) fared poorly compared to cavities in palm (Arecaceae) snags, hardwoods (live and dead), and wood utility poles. In the year after Hurricane Irma, the proportion of new cavities in palm snags increased relative to other substrates, while the proportion of cavities excavated in pines, hardwoods, and utility poles decreased. Trees excavated in the year after Hurricane Irma were 23 % shorter than trees with cavities found before the hurricane, suggesting that available trees were smaller. The decay class of trees and the number of woodpecker holes did not significantly affect the persistence rates of woodpecker cavity trees. We speculate that because palms generally have softer wood, their physical structure could make them more attractive to woodpeckers in the first year after a storm. The results of this study are relevant to the management of dead trees in urban areas in hurricane-prone regions, which are experiencing high urban growth. Cutting urban palm snags immediately following a storm removes a critical resource for woodpeckers during the first year of recovery.