Nest box use by American Kestrels and other cavity-nesting birds during the nonbreeding season

Nest boxes are posted to provide breeding sites for cavity-nesting birds but less is known about their function in the nonbreeding season, when nest boxes may become important roost sites. In winter months, we surveyed 79 nest boxes before dawn for roosting American Kestrels (Falco sparverius) and other cavity-nesting birds in southwestern Idaho and we reviewed camera recordings from the entire nonbreeding season at a nest box within the study site to better understand nest box use in the nonbreeding season. During surveys we found seven American Kestrels roosting in six nest boxes, Northern Flickers (Colaptes auratus) in 16 nest boxes and a European Starling (Sturnus vulgaris) in one nest box. Video recordings revealed inter- and intra-specific conflicts within the nest box as well as a positive relationship between the length of night and the time spent roosting in the box. These results suggest that cavity-nesting birds in our study area are likely to seek out and compete for nest boxes to use as roost sites in the nonbreeding season and the effects of nest boxes on the nonbreeding season ecology of birds should be considered