Meeting Abstract
The timing of breeding is critical in determining reproductive success. As global temperatures have increased in recent decades, many animals have modified their breeding behaviors. Among birds, some species have advanced the timing of reproduction in accordance with temperature increases, whereas other species have failed to adjust breeding time, resulting in mistimed reproduction. We analyzed 25 years of nesting data from Eastern Bluebirds (Sialia sialis) and Carolina Chickadees (Poecile carolinensis), from 38 nest boxes on the University of Southern Indiana campus in Evansville, IN. Between the years of 1973 and 2017, the onset of breeding, measured as the date of the first egg laid by each species, advanced by more than 7 days in bluebirds and 11 days in chickadees. In both species, the advancement in breeding correlates with average surface temperature at the time of breeding. This correlation suggests that Eastern Bluebirds and Carolina Chickadees can adjust breeding phenology based on proximate cues, and may be able to adjust to a changing climate.
