Autumn Olive, Elaeagnus umbellata, has been introduced throughout the United States. Research on the impacts of invasive plants like E. umbellata on bird behavior has produced conflicting results with some birds preferring to use invasives while others avoid them. Branch structure has been implicated in bird preference for certain woody species. Thus, we asked the question, does E. umbellata differ in branch structure from common natives in the landscape and, if so, how does this difference impact the behavior of native birds? We examined this question during the non-fruiting season at study sites with mixed open and shrubby second growth forest habitats in Michigan and Indiana. We found that E. umbellata branches were twice as dense and 45% smaller in diameter than those of native cherry, Prunus serotina, but did not differ from two other native shrubs. Birds did not show a preference for perching in native shrub branches in choice tests using bird feeders in situ with invasive or native branches. Mist net capture rates for birds also did not differ between E. umbellata and native shrub sites. We concluded that native birds do not avoid E. umbellata during the non-fruiting season for perching despite a unique branch structure.
Herakovich, Heather; De Vries, Marcy; and Eberhardt, Laurie, "Does Branch Structure of an Invasive Shrub (Elaeagnus umbellata) Alter Bird Perching Behavior?" (2012). Celebration of Undergraduate Scholarship. Paper 151.