TECHNIQUES FOR CAPTURING BIRDS INSIDE NATURAL CAVITIES

Techniques developed over the course of a long-term study of Acorn Woo dpeckers (Melanerpes formicivorus) for reaching and opening nest and r oost holes and for capturing adults at natural cavities are described. Holes are reached using ladders or technical climbing gear. Cavities are opened by sawing removable ''doors'' that allow one to reach insid e and can then be nailed back in place. Adults are captured by trappin g them at nests or roost holes by means of a plastic bobber set so as to allow one to block the cavity entrance by pulling a string from the ground. These methods help make the capture and study of birds using natural cavities practical.