I tested the effectiveness of squirrel excluder devices (SQEDs) in deterring southern flying squirrels (Glaucomys volans) from using artificial red-cockaded woodpecker {Picoides borealis) cavities by placing them on approximately one-half of the cavities in 14 inactive recruitment clusters on the Savannah River Site, South Carolina. SQEDs consisted of 2 pieces of 35.5-cm wide aluminum flashing placed 7.6 cm above and below the cavity entrance. Cavities with (/V = 37) and without (7V = 35) SQEDs were checked once per month from February 1995 to January 1996; all flying squirrels found in cavities were removed and destroyed. Cavities with and without SQEDs did not differ in cavity height (P = 0.70), distance to first branch >1 m in length (P = 0.09), distance to the nearest tree (P = 0.29), number of trees within 8 m (P = 0.82), or previous use by flying squirrels (P = 0.67). Flying squirrels used cavities without SQEDs throughout the year and occupied 5.7% to 38.2% of the cavities/month. In contrast, only 1 flying squirrel was found in a cavity with a SQED; thus, SQEDs effectively impeded flying squirrels from using red-cockaded woodpecker cavities and should be considered a tool in redcockaded woodpecker management where flying squirrels are a potential threat to population stability or expansion.
