Translocation of Red-Cockaded Woodpeckers by Reciprocal Fostering of Nestlings

Abstract

The endangered red-cockaded woodpecker (Picoides borealis), a nonmigratory, cooperatively breeding species limited to the older-growth pine forests of the southeastern United States, requires living pine trees for cavity excavation. Since the 1950s, alteration and destruction of critical woodpecker habitat have caused a decline in red-cockaded woodpecker populations. The red-cockaded woodpecker now exists mostly in small, scattered populations whose respective members have little opportunity to interbreed. In general, as populations become smaller and more isolated, the frequency of inbreeding increases and genetic diversity and population viability may decrease. The introduction of unrelated individuals into disjunct red-cockaded woodpecker populations may reduce inbreeding, maintain genetic variability, and reduce local extinction. We developed a technique for selecting red-cockaded woodpecker nestlings and transferring them into the nests of unrelated conspecifics. For each translocation, we paired nests by age and exchanged 1 nestling from each, so that 2 introductions were made with 1 reciprocal translocation event. Nest visitation by the parents and fledging success of nestlings were monitored. Fostered nestlings were accepted by their new parents, and the rate of successful fledging by fostered nestlings was not different from that of nonfostered control nestlings. We concluded that reciprocal intraspecific fostering of similarly aged nestlings can be used safely and effectively to translocate red-cockaded woodpeckers and may have advantages over the translocation of adults and juveniles under certain conditions.