REVISIT SCHEDULE DOES NOT AFFECT RESULTS OF POINT COUNTS

Abstract

We compared two fixed-radius point count sampling regimes using two abundant breeding species, the Dark-eyed Junco (Junco hyemalis) and the Chestnut-sided Warbler (Dendroica pensylvanica), in a forested landscape in the southern Appalachian mountains of Virginia. The same 20 points were counted three times under each of two revisiting schedules, either hourly or weekly, and the maximum and mean number of males recorded. Revisit schedule had no detectable effect on numbers of either species recorded, regardless of whether the fixed radius was 50 or 100 m or whether count duration was 5 or 10 min. For juncos, the maximum number of birds detected using an hourly revisit schedule with a 100-m fixed-radius count circle and a 5-min or 10-min count duration provided close matches to the density estimated by intensive territory mapping of this color-banded population (0.398 males/ha or 0.298 males/ha respectively, versus 0.325 known breeding males/ha). When revisiting count stations is desirable, the use of a 1-h revisit schedule provides an economical way to increase number of visits, with no apparent reduction in precision or accuracy of the estimate.