Avian nest site selection and reproductive success

Populations of cavity-nesting nesting songbirds have been declining throughout the globe. Cavity-nesting birds (those that require a tree hole or artificial nest box to reproduce) can benefit from conservation management efforts that establish potential nesting sites, buffering such populations from local decline. Many questions, however, are unanswered in regards to best management practices to bolster cavity-nesting species. We hypothesized that bird species differ in their nest site selection for boxes composed of either cedar wood or a Schwegler™ mix of concrete, sawdust, and clay. In December 2015, one of each type of box was erected in pairs across the Missouri Western State University campus. From March through July in 2016 and 2017 boxes were fitted with iButton temperature loggers and monitored every 3-4 days for breeding activity. Temperatures in Schwegler™ mix boxes were significantly higher with greater daily fluctuations. Black-capped Chickadees (Poecile atricapillus) and Eastern Bluebirds (Sialia sialis) significantly preferred Schwegler™ mix nest boxes, with no attempts made in wood boxes. This was despite the fact that wood boxes were cooler during the warm months of May-July. House Wrens (Troglodytes aedon) nested later in the season, and although there was no difference in the composition of boxes selected, significantly more House Wren young fledged from concrete boxes. These results are scientifically significant because knowledge of nest box preferences and temperature differences that may affect nesting success allows managers to target specific species of interest and support re-introductions of species of conservation concern.