Joel Green­berg has spent most of his life in the Chica­go region and has been inter­est­ed in nat­ur­al his­to­ry since child­hood. He spent his career in envi­ron­men­tal pro­tec­tion work­ing for gov­ern­men­tal and pri­vate enti­ties. He has writ­ten numer­ous arti­cles and has authored or coau­thored four books, includ­ing A Nat­ur­al His­to­ry of the Chica­go Region and A Feath­ered Riv­er Across the Sky: The Pas­sen­ger Pigeon’s Flight to Extinction.