BIOLOGIST CHRIS RAY felt something tug at her shoe as she sat in a steep boulder field at 10,000 feet in Montana's Gallatin Range waiting for a female pika to emerge from the rocks. Pikas are fuzzy, potato-sized herbivores that inhabit the tops of Western mountains. Frantic workers, they collect large piles of wildflowers and grasses during summer--a process called haying--to eat during winter