Humans have increased interactions between species who did not evolve together and therefore lack behavioral adaptations that would be present if they had. These “novel interactions” can be harmful for native species and may eventually lead to their extinction. House wrens (Troglodytes aedon) are one such species that are commensal with humans and have spread in their distribution, resulting in novel interactions. Young Harris, Georgia is one such place where this has occured. Here, house wrens pose a threat to native, cavity-nesting birds because house wrens exhibit infanticidal behavior when competing for limited nesting cavities. Carolina chickadees (Poecile carolinensis) are cavity nesters that are affected by house wrens; however, since house wrens are only a recent addition to the avian assemblage of Young Harris, the question remains if the chickadees have evolved anti-predatory behavior against the house wren. Preliminary data from last year suggest that half of the local Carolina chickadee population respond adaptively to house wrens. Therefore, we hypothesized that some, but not all, Carolina chickadees around Young Harris respond adaptively to house wrens. We used 100 nest boxes and checked them during the breeding season (March – June, 2018) for nesting Carolina chickadees. When nestlings were 8 days old, we filmed the box for an hour to document parental nest visitation rate. After one hour, we placed a model near the box, which was either a mourning dove (negative control), a squirrel (positive control), or a house wren (experimental treatment). We then filmed for another hour to document the change in visitation rate for a within-subject design. We then compared the responses of Carolina chickadees to the house wren, squirrel, and mourning dove to determine if they treated house wrens as a predator. We will analyze the data to determine if Carolina chickadees have evolved behavior to account for house wrens.


We thank the various land owners who allowed us to install bird boxes on their properties, including Young Harris College, Brasstown Valley Resort & Spa, Brasstown Valley Golf Course, and many others. We could not have accomplished this without the continued support of the faculty, students and staff at Young Harris College. We are also deeply grateful to the funding recieved from the Young Harris College Undergraduate Research Fund and the Highlands Plateau Audubon Society.

This document is currently not available here.