Vince, Michigan, Wisconsin, and Minnesota have joined together to pool data and results for a little over three years to track West Nile Virus (WNV) impacts on Ruffed Grouse numbers in the Upper Midwest. A great deal of their baseline reference information has come from existing studies in Pennsylvania. Recently, study data funded by the Ruffed Grouse Society concluded that WNV induced mortality could run as high as 90%. From what I recall this was done at Colorado State University. Anitbodies to WNV have ranged from a little over 10 to as high as 25% in second year birds in Michigan data, so birds are surviving. The Pa. multi-year data concludes that managing for optimal habitat maximizes WNV survival among juvenile birds. Concomitant with this data on survival rates, having continquous blocks of optimal habitat enables dispersal of disease resistant birds into adjacent blocks of cover, enabling population recovery rates to progress relatively rapidly. Some data from MDNR's Rose Lake Research laboratory indicates that small intermittent surface water is the chief culprit in enabling Culex restauns rather than the more common Culex pipiens to propogate. Culex restauns disperses to the mid-canopy section of forested cover and is primarily an avian blood predator, distributing within the canopy at about the same time of day the grouse move to bud and feed.. Vernal and temporary wetlands with a complex invertebrate community consisting of water boatman, water striders, Odonate larvae, salamanders, and diving beetles contain enough mosquito larval predators to hold numbers of emerging adults relatively low, unlike these smaller sheetwater pools that don't last long enough or establish on a routine enough basis to contain larval predators in numbers that enable population control to any great degree
The other broad benefit of ruffed grouse habitat enhancement efforts: when you manage for grouse, you manage to benefit whitetail deer as well.
