Friday, August 24, 2012

NY State 2012 Ruffed Grouse Drumming Report

During the spring 2012 wild turkey hunting season, DEC conducted the sixth 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.
You can view, print, or download the complete 2012 Ruffed Grouse Drumming Survey Report (PDF) (779 kB).
We thank all the hunters that participated in the Ruffed Grouse Drumming Survey during the 2012 season.

Results from the 2012 Season

During the 2012 season, 157 hunters participated in the Ruffed Grouse Drumming Survey. Survey participants reported data from over 1,000 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 3,900 hours afield and observed just over 700 grouse (about 0.20 birds/hour). Some general findings from the 2012 season include:
  • Hunters participating in the survey averaged about 25 hours afield during the 2012 season. They took about 7 trips afield for the season and spent almost 4 hours afield per trip.
  • Survey participants averaged about 4.5 grouse observed per hunter for the 2012 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 of the season (May 1-7); however, the drumming rate (grouse drumming/hour) was relatively consistent (0.24 birds/hour) for the first two weeks of May.
  • Overall, there was far more effort expended in the southern grouse season zone (about 83% of the total), but the drumming rate was similar between the two zones (0.21 grouse drumming/hour in the northern zone vs. 0.20 grouse drumming/hour in the southern zone).
  • Significantly more effort was expended, and more grouse were observed, on private land than public land; however, public land had a higher drumming rate.
  • Survey effort was distributed across major geographic regions of New York State. About 35% of the effort took place in western New York (14% DEC Region 8, 21% DEC Region 9), about 30% in central New York (DEC Region 7), about 25% in the southeastern portion of the State (8% DEC Regions 3, 17% DEC Region 4), and 11% in northern New York (8% in DEC Region 5 and 3% in Region 6).
  • We observed the highest drumming rate in DEC Region 6 (0.29 grouse drumming/hour), but Region 7 was also above the annual statewide average of 0.20 grouse drumming/hour.
  • The drumming rate was highest in the St. Lawrence Valley Ecozone (0.93 grouse drumming/hour), followed by the Adirondacks-Tug Hill Ecozone (0.25 grouse drumming/hour). The Appalachian Hills & Plateau, Catskills-Delaware Hills, and Champlain Valley ecozones were similar to or slightly above the statewide average.

Comparing 2012 to Previous Seasons

  • Since this survey started in 2007, almost 500 turkey hunters took over 6,400 trips afield and spent almost 25,000 hours recording their grouse observations. Over the past six 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 2011 to 2012 the number of survey participants, and the number of trips and hours afield all increased, but the drumming rate declined from 0.25 to 0.20 birds/hour. The amount of time spent afield to hear one grouse drumming increased from 4.7 hours to 5 hours.
  • By almost every measure - total number of grouse drumming, grouse observed/participant, grouse observed/trip, and drumming rate (grouse drumming/hour) - grouse numbers during 2012 were lower than in 2011.
  • Only the Champlain Valley and St. Lawrence Valley ecozones saw an increase in the drumming rate from 2011 to 2012, but it is important to note that due to a small sample size in the St. Lawrence Valley, the results from this ecozone are less reliable than in other regions and the increase was not statistically significant. In fact, survey coverage in much of northern New York is inadequate to reliably estimate drumming rates at the WMU aggregate level (e.g., Tug Hill, Northern Adirondacks). In the future, it will be important to recruit participants in this part of the state to produce an accurate index of grouse abundance there.
  • The drumming rate in the Appalachian Hills and Plateau and Catksills-Delaware Hills ecozones were similar to last year, while the Lake Plains and Mohawk Valley-Hudson Valley-Taconic Highlands ecozones saw declines in the number of grouse drumming/hour from 2011 to 2012.
  • 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 2011, average rainfall was about 3.5 inches above normal statewide, and rainfall was above normal in almost every WMU aggregate in the state, ranging from almost 2 inches above normal in the Hudson valley to 5 inches above normal in the East Appalachian Plateau. This may have negatively affected nest and brood success last year.
  • In areas with a lack of the early successional habitats on which this species depends, 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 and complete NY DEC article

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