Monarch butterfly is now endangered - IUCN

STORY: Monarch butterflies are now listed as endangered

on the IUCN's Red List of Threatened Species

Scientists estimate the butterfly's population

has shrunk by more than 85% since the 1990s

(Karen Oberhauser, Conservation biologist) "There's very good evidence that that early decline for the eastern North American population was due to breeding habitat loss, and that happened because farmers started using crops that they could spray herbicides on without killing the crops, so genetically modified crops, and there actually used to be a lot of monarchs' host plant, milkweed, in corn and soybean fields. But as farmers changed their weed control methods, that milkweed disappeared, and because much of the breeding range of monarchs is used for farming, a lot of that habitat is just gone now, those corn and soybean fields that used to have milkweed growing in them."

The IUCN says over 41,000 species are at risk of extinction

in what scientists are calling the planet's sixth mass extinction event

and the first caused by humans