Recreation Disturbance to a Shrub-Steppe Raptor: Biological Consequences, Behavioral Mechanisms, and Management Implications

• Main Author: Spaul, Robert J.
• Format: Text
• Language: unknown
• Published: ScholarWorks 2015
• Subjects: human disturbance; Golden Eagle; trail management; nest survival; recreation; shrub-steppe; Ecology and Evolutionary Biology; Aquila chrysaetos; golden eagle
• Online Access: https://scholarworks.boisestate.edu/td/995; https://scholarworks.boisestate.edu/context/td/article/2018/viewcontent/Spaul_Robert_J_thesis_August_2015.pdf

With rapid increases in outdoor recreation, and mounting evidence of impacts to wildlife, public land managers and biologists need better information on the nature of this potential disturbance. Outdoor recreation may impact wildlife negatively via human disturbance or habitat degradation. Golden eagles (Aquila chrysaetos) in shrub-steppe habitats face several current and emerging threats, including increased non-motorized and motorized (off-highway vehicle, OHV) recreation. We tested the hypothesis that recreation affects eagle breeding biology by monitoring eagle behavior and reproduction in response to recreation volume and activity types, and landscape features associated with recreation. We also investigated the probability that an adult golden eagle would flush, examined flight initiation distance (FID), and documented total time off the nest following flushing events in response to motorized and non-motorized recreationists. Territories with higher seasonal-average OHV volumes were less likely to be occupied than territories with lower seasonal-average OHV volumes, despite uniformly low OHV volume across all territories during the pre-breeding period. For non-migratory species, like eagles in southern Idaho, decreased occupancy during the breeding season may be the result of carry-over effects of disturbance in the non-breeding season, degraded habitat, or both. At occupied territories, early season volumes of pedestrians and other non-motorized recreationists negatively influenced adult eagle nest attendance and the likelihood of egg-laying. Behavioral observations of breeding birds revealed that adult nest attendance, a strong predictor of success, was associated negatively with the volume of pedestrians, and most pedestrians observed near the nests reached the area via motorized vehicles. In addition, nest survival was affected negatively by interval-specific OHV volume recorded by trail cameras. In most (87.1%, n = 279) instances, adult eagles did not respond to recreationists passing within 1200 m. ...