Researcher Jason Scott, left, reveals the finer points of determining a monarchs gender to volunteer John Matusik. Males have dots on their hind wings; females dont. (Spencer Weiner / LAT)
Closeup of a Monarch butterfly (Spencer Weiner / LAT)
Researchers are conducting the first systematic census of Western monarch butterflies. (Spencer Weiner / LAT)
Monarchs cling to branches in Big Sur. (Spencer Weiner / LAT)
With global warming possibly threatening their survival, researchers are clamoring to better understand their migration. (Spencer Weiner / LAT)
Researcher Jason Scott takes a closer look at a Monarch butterfly. (Spencer Weiner / LAT)
Researchers use binoculars to examine the butterflies. (Spencer Weiner / LAT)
