West Nile Virus and Ruffed Grouse
August 24, 2016
Ruffed Grouse Society
Results of recent West Nile Virus research on ruffed grouse show need for landscape scale creation of young forest habitat.
The recent Pennsylvania Game Commission (PGC) research, with partners including the Ruffed Grouse Society (RGS), on the effect of West Nile Virus (WNV) on ruffed grouse populations is a call to action to create more high-quality young forest habitat at a landscape scale. Although West Nile Virus is an additional stressor, ruffed grouse have a higher rate of survival in regions with high-quality, abundant habitat.
THE RESEARCH: The PGC began the WNV research in 2014 to better understand the impact of the virus on ruffed grouse populations by first conducting an experimental infection trial on chicks hatched from wild-collected grouse eggs in Pennsylvania. Results indicated that WNV caused chick mortality or organ damage to 80 percent of those infected. Samples from hunter-harvested grouse during the 2015-16 Pennsylvania hunting season revealed that wild grouse are exposed to WNV in every region of the state. The WNV does not apply annual and steady pressure on ruffed grouse populations, and the risk to grouse rises and falls over time triggered by weather conditions with varying peaks in other states, regions and time periods. Read more details in the Pennsylvania Game News September 2016 article, pages 2-9: "WHAT'S WRONG with our ruffed grouse?".
HABITAT CONNECTION: The research indicates that regions with high-quality and abundant habitat show a strong grouse population recovery between peak WNV periods, and regions with lower-quality and less abundant, more fragmented habitat show weak recovery and population declines. Individual birds have a higher rate of WNV survival in high-quality habitat.
WHAT CAN WE DO? This WNV research is a call to action to create more high-quality habitat at a landscape scale. Young forest habitat creation and restoration is important due to the onset of WNV as an additional stressor to ruffed grouse populations, and land managers should focus on creating areas with diverse native food sources and thick protective cover.
This research on WNV effects on ruffed grouse will continue into 2016-17. RGS will continue to support the research and the role that habitat management plays in moderating disease impacts.
Ruffed Grouse Society
451 McCormick Road
Coraopolis, PA 15108