BEHAVIORAL AND DEMOGRAPHIC CONSEQUENCES OF ACCESS TO EARLY-SUCCESSIONAL HABITAT IN JUVENILE OVENBIRDS (SEIURUS AUROCAPILLA): AN EXPERIMENTAL APPROACH

Although numerous studies have demonstrated that mature-forest songbirds use successional habitat heavily during the postfledging period, implicit, but yet untested, is the assumption that successional habitat provides high-quality postfledging habitat and promotes juvenile survival. We experimentally tested how access to and use of successional habitat (i.e., regenerating clearcuts) influenced survival and behavior of independent juvenile Ovenbirds (Seiurus aurocapilla). Between 2004 and 2006, we captured and radiotagged 85 Ovenbirds in regenerating clearcuts in southeast Ohio. Radiotagged Ovenbirds were randomly assigned to one of three experimental groups that were released in (1) the original clearcut of capture, (2) a different clearcut of similar age, or (3) a mature forest. Survival of independent juveniles at 52 days was similar among experimental treatments, at 83%. Juvenile survival tended to increase with understory vegetation density and individual energetic condition. Juveniles selected habitat characterized by dense understory vegetation, including large patches of early-successional habitat as well as microhabitats within the mature forest (e.g., riparian thickets, treefall gaps, and forest edges). Ovenbirds released into mature forest habitat traveled farther from their release location after both 7 and 14 days than birds released in clearcut treatments. Although juveniles tended to select dense understory cover during the postfledging period, high juvenile survival did not require large patches of successional habitat. Received 17 January 2012, accepted 27 September 2012.