Pileated woodpecker damage to red-cockaded woodpecker cavity trees in eastern Texas
Abstract
The authors surveyed all known red-cockaded woodpecker (Picoides borealis) cavity trees (n = 514) in the Angelina National Forest in eastern Texas for pileated woodpecker (Dryocopus pileatus) damage. They compared the frequency of pileated woodpecker damage to red-cockaded woodpecker cavity trees in longleaf pine (Pinus palustris) habitat to damage in loblolly (P. taeda)-short leaf (P. echinata) pine habitat. The authors also examined the effectiveness of restrictor plates in deterring pileated woodpecker enlargement of red-cockaded woodpecker cavities. Pileated woodpecker damage was significantly greater in longleaf pine habitat than in the loblolly-shortleaf pine habitat, in spite of census results showing similar abundance levels of pileated woodpeckers in the two forest types. The authors suggest that limited numbers of snags in the longleaf habitat may focus pileated woodpecker excavation on red-cockaded woodpecker cavity trees, whereas a greater amount of mid-story vegetation in the loblolly-shortleaf pine habitat may serve to reduce visibility, thereby lowering pileated woodpecker detection and destruction of red-cockaded woodpecker cavities. Restrictor plates were very effective in preventing pileated woodpecker enlargement of cavities. While restrictor plates are useful for protecting red-cockaded woodpecker cavities, they should be used only in small populations when cavities are in short supply. The pileated woodpecker plays an important role, especially in the longleaf ecosystem, which is a relatively cavity-barren environment, by providing nesting sites for larger secondary cavity users, such as American kestrels (Falco sparverius), eastern screech-owls (0tus asio), and fox squirrels (Sciurus niger).