Hundreds of monarch butterflies raised by inmates at the Washington State Penitentiary at Walla Walla are being released this month to fly over the walls and help researchers learn about their migration patterns.
About 40 inmates raise the butterflies, feeding the caterpillars until they turn into winged insects.
The research is led by Washington State University associate professor of entomology David James. The butterflies carry a small tag with his email address. People who find them contact him.
Two monarchs from last year's release were found -- one in Utah and one north of San Francisco.
Prison officials say the butterfly program is therapeutic for inmates and improves their behavior.