A new study shows that herds of the iconic ungulate are rearing fewer young as oil and gas wells, renewable energy developments and trees spread into their rangeland habitats and migration corridors.By Najifa FarhatPronghorn in Wyoming are experiencing long-term declines in the number of young they are rearing due to increased oil and gas development and encroaching woody vegetation, according to a new study. Although pronghorn populations in Wyoming have been largely stable, the new analysis shows that many herds are experiencing long-term declines in fawn production.