Where are the butterflies?

Maybe your experience has been different this summer, but I feel like I’ve seen a lot fewer butterflies than usual. From Virginia to Ohio to Texas, reports of fewer butterflies have been common in the news, a continuing trend over the past couple of decades. Nationwide, butterfly populations are declining due to the usual suspects — habitat loss, climate change and pesticides.

According to a study published in the journal Science, the number of butterflies in the U.S. fell by 22% between 2000 and 2020. And for the monarch, one of America’s most favorite butterflies, toastier fall weather might cause migrating butterflies to wing it and change their flight plans. Many of the monarchs exposed to higher temperatures began breeding in the migration phase, leading to females laying eggs despite the lack of milkweed.

So what can we do? Basically, nothing, but in a good way. Letting some part of your yard go unmown and unweeded can boost the number of butterflies and moths sighted there, says ecologist Richard Fox. In a yard surrounded by other houses, long grass could boost butterfly abundance as much as 18%. For yards surrounded by farms, the increase could be as large as 93%.