Nest usurpation by non‐native birds and the role of people in nest box management

Abstract

AbstractInvasive species are a threat to global biodiversity, yet the impacts of invasive birds on the native birds with which they compete are understudied. Humans have a long history of providing and managing nest boxes to support native birds; however, their management of non‐native birds has received limited research attention. We surveyed people who maintain nest boxes in North America to examine the extent of interference competition for nest sites between native and non‐native birds and the human behaviors intended to reduce nest site competition. Our specific objectives were to examine observations of nest usurpation of native birds by non‐native birds across the United States and Canada, to ascertain whether and how people who maintain nest boxes control non‐native bird species in favor of native species, and to quantify various factors correlated with the likelihood of engaging in management activities. We found that nearly one‐third of the 871 respondents had observed a non‐native species usurp a nest box occupied by a native species. Among respondents who reported nest usurpations, species‐specific nest usurpation rates varied (range = 3–35%). We found that witnessing a nest usurpation is the most important predictor of whether or not someone will engage in management activities. Management activity was also associated with the extent to which respondents believed non‐native birds to be a problem at the continental scale. Our study shows that people's observations of threats from introduced species are correlated with the environmental management actions people take, and that these actions can mitigate the threats, and potentially support the survival of native birds.