Effects of Sudden Oak Death-induced habitat change on insectivorous, cavity-nesting birds
Kyle Apigian1 and Donald L. Dahlsten1
Abstract: Sudden Oak Death (SOD) has killed thousands of trees in oak woodland in 12 coastal California counties. Such disease induced habitat changes can have severe impacts on wildlife populations by altering their resource base. For example, forest dieback can result in declines or changes in insect populations, which can subsequently impact insectivorous birds by forcing them to switch prey items, change foraging substrates, or increase foraging time. Ultimately, this can impact the nesting success of these bird species. The goal of this study is to examine the effects of SOD-induced stand structure changes in oak woodlands on insectivorous cavity nesting birds, particularly oak titmice (Baeolophus inornatus) and chestnut backed chickadees (Poecile rufescens). We are examining the impacts of SOD on these species on two levels: the population ecology level by studying nesting success and productivity and the behavioral ecology level by studying diet composition, foraging behavior, and habitat use. This study is part of an integrated, collaborative study (Allen-Diaz and O'Hara labs, UC Berkeley, ESPM) on the ecological effects of SOD that utilizes common, 1-ha study plots established in SOD infected (treatment) and uninfected (control) areas. We will present background for our component of the study, our methods, and preliminary results from the spring of 2002.
1Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720
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