Nest Site Selection by Red-Naped Sapsuckers : Influence of Willow Availability, Aspen Heartwood Rot Fungus, and Other Ecological Factors.

Abstract

Woodpeckers are considered keystone species because they excavate tree cavities that provide habitat for other cavity nesting species. In aspen (Populus tremuloides) woodlands of the southern Rocky Mountains, red-naped sapsuckers (Sphyrapicus nuchalis) are the predominant woodpecker, providing essential nest cavities for multiple bird species. Sapsuckers also create sap wells in willows (Salix sp.) and aspen, providing food for many species. Previous work indicated that sapsucker nest densities decreased strongly with distance from willows. However, previous work did not account for potentially confounding effects of other variables such as the prevalence of the heartwood rot fungus, Phellinus tremulae. The sapsuckers nest almost exclusively in Phellinus-infected aspens. To properly conserve the sapsucker-associated community we need to better understand the ecology of Phellinus and relationships among multiple factors aspen-willow--Phellinus system.