Winter Space Partitioning of Woodpeckers and Nuthatches in Wisconsin

Woodpeckers and nuthatches are resident species sharing similar year-round habitat in northeastern North America, but little is known about how these species distribute themselves within the same wintering area. From 2009 to 2015, we conducted a mark—recapture study of 7 Downy Woodpeckers, 15 Hairy Woodpeckers, 9 Red-bellied Woodpeckers, and 39 White-breasted Nuthatches to determine geographical winter home-range partitioning between and within species. We used multinomial log-linear models to estimate the likelihood of capturing each species in a particular baited trap when other species had been caught in the same trap during the same year. Our results show the presence of each species influenced the likelihood at least 1 other species would inhabit the same area. Most of these relationships were positive and indicate active sharing of the same space. However, Hairy Woodpeckers appeared to deter White-breasted Nuthatches, and Red-bellied Woodpeckers avoided conspecifics. Little evidence of space partitioning suggests minimal competition occurs during winter months between these species. Since these species occupy similar habitats, the appearance of one may indicate suitable habitat influencing the presence of others.