Effects of southern flying squirrels on nest success of red-cockaded woodpeckers

Recovery efforts for endangered red-cockaded woodpeckers (Picoides borealis ) often include control of southern flying squirrels (Glaucomys volans). Ne vertheless, few studies demonstrate directly that this control improves nes t success of red-cockaded woodpeckers, and no experimental studies have eva luated what form of flying squirrel management is most effective. Therefore , in 1996 and 1997 at Fort Stewart, Georgia, we quantified the nesting succ ess of red-cockaded woodpeckers in 30 cavity-tree clusters from which flyin g squirrels were removed, 30 clusters in which flying squirrels were exclud ed from cavities with squirrel-excluder devices, and 30 control clusters wi th no flying squirrel management. Removal or exclusion of flying squirrels did not affect the likelihood that red-cockaded woodpeckers would initiate a nest or the median date the first egg was laid in either year. In 1996 (b ut not 1997), red-cockaded woodpeckers were more likely to nest successfull y (produce greater than or equal to 1 fledgling) in clusters from which fly ing squirrels were removed. However, in both years of our study, nests in f lying squirrel removal clusters were more likely to experience partial nest loss (disappearance of a portion of their eggs or nestlings). As a net res ult, the number of eggs,nestling, and fledglings did not differ among treat ments in 1996 or 1997. Removal or exclusion of flying squirrels did not inc rease the percentage of clusters fledging young or the number of young fled ged per cluster. We suggest routine control of flying squirrels is not need ed in healthy populations of red-cockaded woodpeckers.