Date of Award:
Master of Science (MS)
Frank P. Howe
Lewis‘ woodpeckers (Melanerpes lewis) are generally associated with open ponderosa pine (Pinus ponderosa), open riparian, and burned pine habitats in the West; however, this species has recently been found to nest in aspen (Populus tremuloides) stands in Utah. This study describes the habitat characteristics of Lewis‘ woodpecker nest sites in aspen and investigates how well aspen stand characteristics predict Lewis‘ woodpecker occupancy. I surveyed for Lewis‘ woodpeckers at previously occupied nesting locations in aspen and took habitat measurements at nest sites. In addition, nest-centered Forest Inventory and Analysis (FIA)-type plots provided stand-level habitat characteristics. I used logistic regression to determine which stand-level habitat variables were associated with nest locations; significant variables were then used to select FIA plots in Utah that contained predicted suitable nesting habitat. Criteria used to select FIA plots were aspen type stands, percent canopy cover less than 46%, and average tree diameter at breast height greater than 27.9 cm (11 inches). I then conducted occupancy surveys at FIA plots predicted to contain “suitable” and “non-suitable” Lewis’ woodpecker habitat to field validate the predictive model. No predicted non-suitable plots (n=26) were occupied and only one predicted suitable plot (n=49) was occupied. My results indicated that Lewis’ woodpeckers are rare throughout Utah in aspen stands even though there seems to be abundant nesting habitat available. My results also indicated that variables measured by FIA do not, in isolation, provide sufficient capability to predict Lewis’ woodpecker nesting habitat or actual use, and that more data are needed to accurately predict Lewis’ woodpecker nesting habitat, such as distance to, age, and severity of fires.
Vande Voort, Amy M., "Habitat Characteristics and Occupancy Rates of Lewis's Woodpecker in Aspen" (2011). All Graduate Theses and Dissertations. 922.
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