Ruffed grouse (Bonasa umbellus) drumming surveys, 1987-2017, Adirondack Long-Term Ecological Monitoring Program Project No. 9 by Adirondack Ecological Center of the State University of New York College of Environmental Science and Forestry, Newcomb, New York. Environmental Data Initiative

The objective is to document long-term population trends of ruffed
grouse in a northern hardwood ecosystem. The survey area is the
Huntington Wildlife Forest, a 6,000 ha field station which receives no
hunting pressure. Routes are surveyed starting an hour prior to
sunrise on 2-5 mornings each year between April 14 and May 9
(occasionally later), on days when wind and rain are minimal to
absent. Counts are standardized relative to weather conditions and
timing. Observers count the number of individual ruffed grouse heard
drumming (""drummers"") at 32-50 route stations
during a 4-minute period. Trends at stations over time as well as
overall drummer index are calculated and compared to independent
datasets.