Bird data
At each of the 24 preselected terrestrial forest NEON sites, we eliminated non-forest points and identified forest ecosystem type using the continental U.S. and Alaska Forest data (Ruefenacht et al., 2008). Based on these criteria, we compiled avian point count data for 253 survey points. The NEON point count method is adapted from Hanni et al. (2017). Depending on the size of the site, sampling occurs at randomly distributed individual points or 9-point grids. At larger sites, point count sampling occurs at five to fifteen 9-point grids. At smaller sites, point counts occur at the southwest corner of 5-25 distributed vegetation plots. Point counts are conducted once per breeding season at large sites and twice per breeding season at smaller sites. For larger sites, only the center points were used in our analyses to limit spatial autocorrelation and better match surveys from smaller sites. Prior to analysis we removed all non-forest/shrub bird species. Of the 343 species of birds detected across all sites, 231 species are dependent on forest habitats (IUCN, 2019).