2023 Annual Bighorn Sheep Performance Report | Dr. Joel Berger
” Visitation to the Moab realm continues to increase with recreationists who hike, bike, soar, raft, and use two-and four-wheeled vehicles from jeeps to SUVs, spiders to side-by-sides. There’s been increasing concern over possible impacts to our bio-culturally most represented species, particularly in petroglyphs – desert bighorn sheep. And, of course desert bighorns still persist and eke out a tough existence with all of us in their prized habitats.
My work across the past five seasons is asking ‘what are the impacts to desert bighorn females?’. My efforts combine natural observations with experiments in which I play the sounds of people (talking, and motorcycles) through a speaker during a female’s most sensitive period – late pregnancy. I also use a gradient approach with different remote sites so that I can understand the extent to which, or if at all, bighorn females may habituate.
To date our findings suggest: (i) heightened flight by female sheep when disturbed near two-track or dirt roads whether the roads are straight or have greater sinuosity; and (ii) disturbance by motorcycles lessens at distances in excess of 200-300 yards but bio-energetic costs (kilocalorie expenditures) increase some 500-1000% when there is more than a single disturbance in the same day. With repeated disturbance sheep abandon these areas, some of which are the best available.” – Dr. Joel Berger
