Effects of Winter Recreation

This study sampled 5,688 interactions between groups of bald eagles, bison, elk, and trumpeter
swans and groups of snowmobiles and coaches during winters 2002–2003 through 2005–2006 to
identify what conditions lead to behavioral responses. Bison responded less frequently (20%) to snowmobiles and coaches than swans (43%), elk (52%), or bald eagles (83%) due to fewer vigilance responses. The frequency of higher-intensity movement responses was similar among species (8–10%). Responses increased significantly if animals were on or near roads, animal groups were smaller, humans approached animals, interaction times increased, or numbers of vehicles in a group increased. Staff did not detect significant changes in the odds of movement responses for any species as cumulative OSV traffic increased through winter. Vigilance responses by bison decreased during the winter that had the largest visitation, suggesting some habituation. Conversely, vigilance responses by elk increased as cumulative visitation increased. Human disturbance was not a primary factor influencing the distribution and movements of bison, elk, and swans. The risk of vehicle-related mortality was quite low and these species used the same core winter ranges despite large winter-to-winter variability in cumulative exposure to snowmobiles and coaches. There was no evidence that snowmobile use during the past 35 years significantly affected the demography of bald eagles, bison, elk, or trumpeter swans. Regulations were effective at reducing disturbances below a level that would cause measurable fitness effects (White et al. 2009).

Updated 7/28/10