Lewis’s Woodpecker nest success and habitat selection in floodplain and burned forests in western Montana

Abstract

For species with declining populations across their range, such as Lewis’s Woodpeckers (Melanerpes lewis), understanding habitat selection and its influence on reproductive outcomes are critical for effective management, especially in human-modified landscapes. We identified factors associated with habitat selection by Lewis’s Woodpeckers in the floodplain and burned forests across the Bitterroot Valley in Montana. We estimated population densities, determined reproductive outcomes, and examined the possible influence of forest characteristics on nest-site selection. Mean adult population densities of Lewis’s Woodpeckers were over three times greater in floodplain forest than burned forest (13.2 adults/km² vs. 4.1 adults/km², respectively). However, nest success was lower in floodplain (73%; CI = 62%, 82%) than in burned forest (88%; CI = 78%, 94%). Nest success also declined across the breeding season. Lewis’s Woodpeckers in the floodplain forest were more likely to nest in cavities in taller trees, forested areas with reduced canopy cover, and stands with more trees. In burned forests, the height of nest trees was the only distinguishing feature of nest-site selection. However, the characteristics of nest sites used by Lewis’s Woodpeckers did not predict nest success. Ultimately, nest success was high in both forest types and both play an important role in maintaining populations of Lewis’s Woodpeckers in our study system. Management strategies to conserve habitat for Lewis’s Woodpeckers in western Montana should focus on retention of trees and snags > 18 m in height in both forest types, as well as enhancing recruitment of cottonwoods in a floodplain forest.