Nest Box Microclimates and Parental Care Behavior: A Suburban and Rural Comparison

Nest boxes are often used to supplement or replace lost natural cavities. Although nest boxes are a common tool in conservation, their microclimates can be different from natural tree cavities, and they may be less insulative than natural cavities. Potentially hotter and drier artificial cavities may influence incubation, feeding behavior, and fitness of birds using them. This effect can be further exacerbated in habitats with less canopy cover such as urban and suburban areas. By comparing nest boxes used by Thryothorus ludovicianus (Carolina Wren) nesting in a suburban and a rural habitat, I hoped to better understand how nest-box microclimates can affect incubation behavior. I monitored internal and external temperature and humidity of the nest boxes with active wren nests. Video recordings of incubation behavior and feeding behaviors were taken during morning and afternoon sessions for two-hour periods. Despite differences found in temperature and humidity, I did not find significant differences between incubation and feeding behavior correlated with the differences between the rural and suburban habitats. Clutch size was found to be correlated with temperature while percentage of eggs hatched, and fledgling success were not strongly correlated with temperature, humidity, or habitat. With expanding urbanization and rising temperatures, understanding how to manage nest boxes to better aid the animals that use them is essential.