Ross Winton has been spending a lot of time lately catching butterflies in south-central Idaho and putting tiny stickers on their wings. That’s so they can be identified by scientists who see them in other places. But Winton, a biologist with Idaho’s Department of Fish and Game, thinks now the last of them may have moved out of state for the season. Winton is part of a regional monarch butterfly study. He says scientists know in great detail where a monarch born in upstate New York or Michigan or Northern California will travel in its life.
“There’s been very little work done west of the Rockies outside of California,” he says. “So we’re really trying to get a grasp on exactly where monarchs reared in Idaho, where they actually go as far as their migration paths.”
Monarch butterflies have been getting a lot of attention in recent years because they face serious threats to their survival. Monarchs are important to ecosystems throughout North America because of their role in pollination. This focus has meant their remarkable, continent-spanning migration routes have been studied minutely. But Winton says the West represents a big gap in that knowledge.
The monarch butterfly is Idaho’s official state insect. Winton says they’re not as important to pollination in Idaho as they are in other parts of the country, but he says they’re needed to pollinate some flowers that bloom in late summer. He says understanding Idaho monarch migration is important in the larger effort to protect the species.
Monarchs show up in Idaho in spring or early summer. We don’t know where they come from. When they arrive they mate, lays eggs and die. The eggs hatch and that caterpillar will turn into a butterfly, mate and die in Idaho. Then the grandchildren of the ones who arrive will fly south. We don’t know where they go.
Winton guesses that Idaho monarchs winter in Mexico, like those born in the Midwest.
“Who knows, they could be different,” he says. “Just because we are in kind of a unique place, they could get funneled to a completely different spot. But we really don’t know.”
Some west coast monarchs fly to Southern California for the cold months.
Among the other things scientists want to know, Winton says, is whether the same butterflies return to Idaho to mate, or stop further south and then their offspring continue the journey to Idaho.
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