Charles van Riper III Steven S. Rosenstock 2001 <p>In recent times, pinyon (<i>Pinus spp.</i>)-juniper (<i>Juniperus spp.</i>) woodlands have expanded into large portions of the Southwest historically occupied by grassland vegetation. From 1997-1998, we studied responses of breeding birds to one-seed juniper (<i>J. monosperma</i>) woodland expansion at 2 grassland study areas in northern Arizona. We sampled breeding birds in 3 successional stages along a grassland-woodland gradient: un-invaded grassland, grassland undergoing early stages of juniper establishment, and developing woodland. Species composition varied greatly among successional stages and was most different between endpoints of the gradient. Ground-nesting grassland species predominated in uninvaded grassland but declined dramatically as tree density increased. Tree- and cavity-nesting species increased with tree density and were most abundant in developing woodland. Restoration of juniper-invaded grasslands will benefit grassland-obligate birds and other wildlife.<br></p> application/pdf 10.2307/4003238 en Society for Range Management Breeding bird response to juniper woodland expansion article