Ruffed Grouse Ecology
Grouse Priority Area Siting Tool (G-PAST)
The ruffed grouse (Bonasa umbellus) is a medium-sized game bird with dappled, grayish or reddish barred and spotted coloration - it is hard to see in its native habitat. It has a small crest and a tail which the male fans out in display to attract females. The males also produce a drumming sound, typically while perched on a log, as well.
Ruffed grouse range has been shrinking over recent decades due primarily to naturally occurring forest maturation. Human activities, such as development and changing land-use patterns, have also reduced suitable habitat. Ruffed grouse need young forest habitats (i.e., forests less than 20 years of age) to thrive and can be abundant when such habitat exists. In New Jersey, grouse were generally found statewide but were more prevalent in the hardwood forests of our northern counties than in the southern pinelands.
Forested lands in the New Jersey encompass 2 million acres (40%) and are about equally distributed among private (47%) and public (53%) landowners. Unfortunately for some wildlife species that rely on young forest habitat, such as American woodcock, golden-winged warbler, and ruffed grouse, only about 100,000 acres (5%) of forest stands fall in the young forest age class statewide, while 69% of stands are at least 60 years of age.
Other threats to ruffed grouse populations include predation, weather, and disease. Adult and juvenile grouse are prey for a variety of other avian species (Cooper's hawk, great-horned owl, and red-tailed hawk) and some mammalian species (bobcat, red fox). Abundant nest predators (raccoon, skunk, snakes) can reduce nest success. In addition to predation, chick survival can be negatively affected by cold and rainy spring weather conditions. Recent research studies in neighboring Pennsylvania seem to indicate that some ruffed grouse populations are also susceptible to West Nile Virus, and a multi-state (including NJ) study to determine prevalence of WNV in ruffed grouse was initiated in 2018.