Red-shouldered Hawks (Buteo lineatus) typically line their nests with fresh branches of coniferous and deciduous trees. We recorded all species of green material present in 63 nests from 2003 to 2005 in suburban Cincinnati in southwestern Ohio, and in 35 nests in Hocking Hills in southeastern Ohio, United States. We identified all trees within 0.08-ha plots at 33 nest sites in southwestern Ohio and 30 in Hocking Hills. Red-shouldered Hawks in southwestern Ohio and Hocking Hills used black cherry (Prunus serotina) branches as a nest lining more frequently than expected, based on Bailey's 95% confidence intervals. Black cherry was found in >80% of nests but present in only 57–58% of the vegetation plots, and composed only 4–5% of the trees in the forests of the study areas. White pine (Pinus strobus), red pine (P. resinosa), and eastern hemlock (Tsuga canadensis) also were used more than expected in both study areas. Black cherry is a cyanogenic species and may provide an advantage to nesting Red-shouldered Hawks by functioning as a natural pesticide.