Nest-site use of the cavity-nesting bird community associated with old-growth longleaf pine forests

The Red-cockaded Woodpecker (Dryobates borealis) was once common in longleaf pine (Pinus palustris) forests of the southeastern United States and played an important role through its excavation of long-lasting cavities in living pine trees. The old-growth forests once inhabited by Red-cockaded Woodpeckers have nearly disappeared, leaving unanswered questions regarding the relationship this keystone excavator had with other cavity-nesting birds in terms of nest-site use. To investigate some of these relationships, we studied nest-site characteristics of 10 cavity-nesting bird species in 4 remnant old-growth stands of longleaf pine in the Red Hills region of southwest Georgia. Each stand featured numerous cavities excavated by Red-cockaded Woodpeckers (.0.6/ha) in addition to cavities excavated in dead trees (i.e., snags) by other species. We quantified nest tree characteristics and assessed the similarity of nest sites selected by different species based on substrate, decay, cavity height, diameter at breast height (DBH), and cavity location. Red-headed Woodpecker (Melanerpes erythrocephalus), Red-bellied Woodpecker (M. carolinus), and Northern Flicker (Colaptes auratus) used large (.40 cm DBH) dead trees in addition to Red-cockaded Woodpecker cavities. These snags were missing most of their tertiary limbs, and often lacked bark. Brown-headed Nuthatch (Sitta pusilla) and Eastern Bluebird (Sialia sialis) exhibited substantial overlap through their use of short, well-decayed snags that were typically very charred from fires and,3 m in height. Although they occurred in low nest numbers, Tufted Titmouse (Baeolophus bicolor), White-breasted Nuthatch (S. carolinensis), and Wood Duck (Aix sponsa) used Red-cockaded Woodpecker cavities exclusively on our sites. Studies of cavity-nesting bird nest-site characteristics in other areas where Red-cockaded Woodpeckers occur are needed to help understand regional differences and the breadth of the role this keystone excavator species could play again in supporting the secondary cavity-nesting community in old-growth forests. Received 4 January 2023. Accepted 24 September 2023.