2013 Drumming Survey Results
During the spring 2013 wild turkey hunting season, DEC conducted the seventh annual Ruffed Grouse Drumming Survey. This survey asks turkey hunters to record the number of grouse they hear drumming while afield. The primary purpose of the survey is to monitor the number of birds drumming per hour (i.e., the drumming rate). Changes in the drumming rate illustrate trends in the grouse population when viewed over time and will provide insight into statewide distributions for this popular game species as habitats change both locally and on a landscape scale.
We thank all the hunters that participated in the Ruffed Grouse Drumming Survey during the 2013 season.
Results from the 2013 Season
During the 2013 season, 236 hunters participated in the Ruffed Grouse Drumming Survey. Survey participants reported data from almost 1,500 hunting trips across the state, from the lower Hudson Valley in the south, to the Adirondacks and St. Lawrence Valley in the north, and the Lake Plains and Allegheny Plateau in far western New York. They spent over 5,900 hours afield and observed just over 1,100 grouse. Some general findings from the 2013 season include:
- Hunters participating in the survey averaged about 25 hours afield during the 2013 season. They took about 6 trips afield for the season and spent almost 4 hours afield per trip.
- Survey participants averaged about 4.8 grouse observed per hunter for the 2013 season and had to spend 5 hours afield in order to hear one grouse drumming.
- Almost half of all survey effort took place during the first week May and the drumming rate (grouse drumming/hour) was highest during this portion of the month.
- Overall, there was far more effort expended in the southern zone (about 83% of the total), but the drumming rate was higher in the northern zone (0.41 vs. 0.19 grouse drumming/hour).
- Significantly more effort was expended, and more grouse were observed, on private land than public land; however, public land had a slightly higher drumming rate.
- Survey effort was distributed across major geographic regions of New York State (25% in southeastern NY, 18% in northern NY, 56% in central and western NY). We observed the highest drumming rate in DEC Region 6 (0.56 grouse drumming/hour). The drumming rate was similar, and close to the statewide average, in DEC regions 4, 5, and 7 (0.22, 0.28, and 0.24 grouse drumming/hour, respectively).
- The drumming rate was highest in the St. Lawrence Valley Ecozone (0.73 grouse drumming/hour), followed by the Adirondacks-Tug Hill Ecozone (0.44 grouse drumming/hour). The Appalachian Hills & Plateau, Catskills-Delaware Hills, and Champlain Valley ecozones were similar to the statewide average.
Comparing 2013 to Previous Seasons
- Since this survey started in 2007, almost 600 turkey hunters took over 7,900 trips afield and spent almost 30,000 hours recording their grouse observations. Over the past seven years, grouse numbers increased, peaked around 2009, and have declined since. Whether this is a result of some cyclical fluctuation or is related to the influence of habitat and weather on nest and brood success is unknown.
- From 2012 to 2013 the number of survey participants, and the number of trips and hours afield all increased dramatically. Due to concerns about small sample sizes in some Wildlife Management Unit aggregates, particularly in northern NY, we solicited additional participants from hunters currently enrolled in the Grouse and Woodcock Hunting Log program in the fall. This resulted in over 70 new participants in the spring drumming survey and improved our ability to estimate drumming rates at the WMU aggregate level (e.g., St. Lawrence Valley).
- From 2012 to 2013 the drumming rate increased from 0.20 to 0.23 grouse drumming/hour, but this increase was not statistically significant. The amount of time spent afield to hear one grouse drumming was similar between years.
- Similar to the increase in drumming rate from 2012 to 2013, both the number of grouse observed/participant and grouse observed/trip increased between years.
- Most of northern New York (Adirondacks-Tug Hill, Champlain Valley) saw an increase in the drumming rate from 2012 to 2013. The drumming rate in the St. Lawrence Valley declined about 20% from the previous year, but it was still well above the statewide average at 0.73 grouse drumming/hour.
- The 2013 drumming rate in most of the southern zone was similar to 2012, with the exception of the Lake Plains in western New York, which declined from 0.12 to 0.06 grouse drumming/hour. Both the annual drumming rate and the long-term rate in this ecozone is well below the statewide average due to a lack of suitable habitat in this region.
- Annual variation in grouse abundance is likely a result of variation in weather, including spring temperature and rainfall and winter snow conditions, and food availability during the summer and fall (e.g., hard and soft mast, insects). Data from the U.S. Department of Agriculture National Agricultural Statistics Service indicate that from April 1 through the end of May 2012, rainfall totals were close to normal statewide. This, combined with a relatively mild winter in many areas, may have positively affected nest and brood success and overwinter survival.
- In areas with a lack of the early successional habitats on which this species depends (e.g., Lake Plains, lower Hudson Valley), grouse, their nests, and young are more vulnerable to predation and other limiting factors, thus we tend to observe lower drumming rates in these areas.
Drumming Survey vs. Grouse Hunting Log
- At the statewide scale the drumming rate from the spring survey and the flush rate from the Grouse Hunting Log conducted during the fall seem to be correlated (i.e., when we observe an annual change in the drumming rate, we see a similar change in the flush rate). Based on this, we anticipate that the flush rate during the upcoming 2012-13 hunting season should be up from last fall (0.73 grouse flushed/hour in 2012-13), but below the long-term average flush rate (about 1 bird/hour).
- When we attempt to link drumming rates with flush rates at smaller scales, the results are often inconsistent; drumming rates do not consistently predict flush rates at the ecozone or WMU aggregate level. It is important to note that this is based on only seven years worth of data and the results of the drumming survey and grouse hunting log may be correlated at the ecozone or WMU aggregate level over the long term.