Effects of Road and Trail Characteristics on Mountain Grouse Observations in Western Montana

Abstract

Anthropogenic features such as roads and trails, and human activity may affect space use, demography, abundance, and other wildlife population parameters. Human infrastructure and activity may result in biased population estimates by influencing habitat use of a species and thus abundance estimates within a localized area or the ability of biologist to detect individuals during standard population surveys. To evaluate the effects of anthropogenic features on mountain grouse detections, we developed and conducted replicated surveys throughout western Montana during 2020. Biologists and volunteers collected count data for dusky, ruffed, and spruce grouse during point counts surveys conducted at 582 sites and transect surveys conducted for 291 transects located throughout Montana Fish, Wildlife, and Parks Regions 1-5. Survey transects occurred along two types of human infrastructure: U.S. Forest Service roads with minimal traffic during the survey period and U.S. Forest Service trails. As a first step, we compared count data for road and trail transect surveys for each species of grouse. Overall, raw counts of dusky grouse were higher for transects located along trails (0.59 ± 1.07 SD grouse per transect) than roads (0.33 ± 0.91 SD). Raw counts of ruffed grouse were similar for transects located along trails (0.75 ± 1.42 SD) and roads (0.69 ± 1.55 SD). We did not have a sufficient sample size to evaluate spruce grouse counts.