An automated technique for monitoring nocturnal avian vocalizations
We used audio recording dataloggers known as Frogloggers to collect nocturnal bird vocalizations at eight different sites within the Davy Crockett National Forest and the Stephen F. Austin Experimental Forest in eastern Texas from 9 May 2000 to 31 June 2001. We programmed the dataloggers to record for one-minute intervals at the beginning of each hour starting at 2100 and ending at 0200 DST, for a total of' six minutes at each site per night. Data were collected simultaneously every night. which would nor have been possible using tradition- al bird surveying techniques. We detected vocalizations of a variety of nocturnal and diurnal species. Our technique has the potential to allow determination of the relative sensonal occurrence of' nocturnally vocalizing avian species because we were able to survey every night of the year. This technology, originally developed for amphibian surveys, is proving quite useful in its application to avifauna.