Sylvain Cordier / Monarch butterfly (Danaus plexippus) wintering in Oyamel pine forests (Abies religiosa) Monarch Butterfly Biosphere Reserve / Reserva de Biosfera de la Mariposa Monarca UNESCO World Heritage Site, An...

Floris van Breugel / Monarch butterflies (Danaus plexippus) over winter on Eucalyptus and Monterey Cypress trees near Pismo Beach, San Luis, California, USA December.. When temperatures warm up enough, they will embark on...