monarch clusters

Monarchs gathering in select areas provides a unique opportunity to gauge the health of the population in the West. A group of researchers from the U.S. Fish and Wildlife Service, Winston-Salem State University in North Carolina and the U.S. Geological Survey are testing a new method for estimating monarch populations that could bring increased precision to the current process. Here, overwintering monarchs cluster after a rain storm at Lighthouse Field, Santa Cruz, California.