Rather than being very young ones they were larger, older caterpillars. They moved rapidly through the litter, taking advantage of the lengthening day and the warm weather. They fed voraciously on snow willow, often eating the tops of young buds so, when each leaf opened, a semi-circle of tissue was missing from each. As the summers progressed, many things became clarified about the fritillary's biology. For example, females tend to lay eggs on snow willow, even though another species of willow is equally abundant in Colorado's alpine areas.
Females also prefer willow plants that grow in moist soil and discriminate against dry soil areas.
A truly heartening sign. So, I decided to study a species closely related to the Uncompahgre Fritillary, one that shared the same habitat and, because it is common, one that could be used experimentally. I reasoned that the data from these experiments would help us learn about the Uncompahgre Fritillary and its potential for survival without placing it in peril. In 1995 I turned my transect-walking shoes over to Aaron Ellingson and the Colorado Heritage Program, a program affiliated with the Colorado Nature Conservancy. With the aid of Earthwatch and local volunteers, Aaron and his team have been monitoring the fritillary's population and have succeeded in finding several more colony sites.