Loggers in Mexico may have poisoned 22 million monarch butterflies in an attempt to gain access to protected forestland, says Homero Aridjis, head of the Mexican environmental organization Group of 100. Aridjis said the butterflies, which migrate each winter from Canada to fir forests in the Michoacan state of central Mexico, were found dead on the ground in the last two weeks, with a smell of pesticides in the air. Mexico last fall expanded the size of the sanctuaries set aside for the butterflies, concerned that illegal logging was devastating monarch habitat. Aridjis said the new decree could have provoked the loggers to poison the butterflies. In other butterfly news, the Center for Biological Diversity is suing the U.S. government to protect the rare Sacramento Mountains checkerspot butterfly as an endangered species.