Monitoring ruffed grouse in the Black Hills: Protocol and user's manual for the occupancy spreadsheet program

Abstract

Monitoring ruffed grouse (Bonasa umbellus) in the Black Hills National Forest is a priority for forest managers due to the bird's status as the management indicator species for quaking aspen (Populus tremuloides) and its value to hunters and other recreational groups. We conducted drumming surveys, estimated occupancy, and assessed the influence of sampling and site variables to determine benchmark levels of precision for ruffed grouse occupancy and detection probability estimates. Using these estimates and simulations, we developed a monitoring protocol for ruffed grouse in the Black Hills. We then created a user-friendly program that uses monitoring data in Microsoft Excel to calculate ruffed grouse occupancy and detection probability estimates. (The program is available at https://www.fs.usda.gov/rm/forest-grassland-lab/products/ruffed-grouse-occupancy.) The user's manual herein briefly describes the theory behind occupancy modeling and explains how to enter and analyze data and interpret results from drumming surveys. Additionally, we provide recommendations on which type of occupancy and detection probability estimates should be calculated, depending on the needs of the investigator. The program does not provide precision estimates for heterogeneous occupancy or detection probabilities.