OOS 50-9: Restoring and reintroducing red-cockaded woodpecker populations: The ecological basis for translocation success
Ralph Costa and Roy DeLottele. US Fish and Wildlife Service
Recovery of the federally endangered red-cockaded woodpecker (RCW) requires expanding numerous very small, at-risk populations. Fifteen (52%) of 29 recovery populations and 38 (58%) of 65 recovery properties harbor fewer than 30 RCW potential breeding groups (PBGs). Translocating subadult RCWs to these populations/properties not only prevents local extirpations, but also ensures population growth to a size (30 PBGs) from which continued population expansion can occur without translocations. Since 1989, approximately 1014 inter-population RCW translocations have occurred. Six federal donor populations supplied the majority of the RCWs. Thirty recipient populations, including private, state and federal properties in 11 states, received the majority of the birds. Prior to initiation of the translocation program, these 30 populations, in total, contained 225 occupied clusters, harboring 180 PBGs and 532 birds. In 2006, these 30 populations, in total, contained 475 occupied clusters, harboring 416 PBGs and 1307 birds. We believe the successful translocation of subadult RCWs is founded in the species basic ecology and its habitat requirements. First, both subadult males and females are capable of dispersing and successfully breeding their first year. Second, one method of RCW group formation involves dispersal and occupancy of vacant territories by subadults. Translocation of unrelated subadult pairs to “artificial” recruitment clusters/territories simulates this behavior. Third, survival of subadult RCWs is, in part, dependent on their primary limiting factor, a roost cavity; translocated RCWs are provided this resource. Finally, translocations support the species population demographics (larger, aggregated and dense populations = increased viability) and meta-population behavior.