Eastern Bluebirds (Sialia sialis) do not abandon their chosen nest site in response to a single visit by a nest predator

ABSTRACT We investigated whether visual cues of a nest predator at the nest site prior to the completion of nest building would induce Eastern Bluebirds (Sialia sialis) to abandon their nesting attempt and switch to another box 10 m away. Upon detecting the onset of nest building in one of the paired boxes, we presented the birds with either a visual predator cue (a rubber black rat snake (Pantherophis obsoletus) or a visual control cue (a model Northern Cardinal (Cardinalis cardinalis) on the active nest box for 15 min and recorded the responses of the resident pair of bluebirds. We returned 1 week later to determine whether the presentation of the snake or cardinal resulted in no change, a switch to the other box, or abandonment of the box pair. Although the bluebirds seemed to respond more negatively to the model snake, we found no significant difference in their propensity to abandon the box pair (vs. remain in one of the paired boxes). We found a similar majority of bluebirds continued to nest in the...