Comparison of red-cockaded woodpecker (Picoides borealis) nestling diet in old-growth and old-field longleaf pine (Pinus palustris) habitats

摘要

Automatic cameras were used to record adult red-cockaded woodpecker (Picoides borealis) nest visits with food for nestlings. Diet of nestlings on or near an old-growth longleaf pine (Pinus palustris) remnant in southern Georgia was compared to that in longleaf pine stands established on old farm fields in western South Carolina. Diets of nestlings were expressed as percent nest visits and percent prey biomass. The method of calculating nestling diet composition had little effect on the relative ranking of prey. Roaches (Blattaria: Blatellidae) were the most common arthropod fed to nestlings, ranging from 33--57% of the prey brought to nest cavities by adults or 55-73% of the prey biomass. Other common prey were spiders, centipedes and caterpillars. The latter were primarily larvae of coneworms (Lepidoptera: Pyralidae, Dioryctria spp.) that bore into and feed on pine cones. Scorpions (Scorpiones: Buthidae, Centruroides sp.), an unusual prey, were recorded several times at the south Georgia location. Morisita's index (C) of diet overlap showed a high degree of similarity in nestling diets among years in the old-growth remnant (C = 0.91 to 0.94), as well as a high degree of similarity in the diets of nestlings among woodpecker groups within locations and between old-growth and old-field habitats (C = 0.89--0.95). Our study shows that old trees on relatively undisturbed sites provide the same prey as younger trees growing on old farm fields and the relative importance of the different prey was similar for both habitats.