Western Monarch: Way Down, But Not Out

You may have heard about the alarming and sad decline of the Western Monarch, the population of monarch butterflies that lives and moves west of the Rocky Mountains. This past winter, citizen scientists counted the overwintering population in California at under 2,000 individuals. This is down from over a million individuals counted in the 1990s. Such decline has understandably stoked talk and fears of extinction. But one local scientist isn’t so sure. David James, Washington State University Professor of Entomology, offers some perspective and hope for the future of this beautiful and iconic insect.

James considers the monarch an adaptable and resilient species that is likely to persist in the west. In a recent piece published in the journal Animal Migration, James points to a curious increase in breeding populations of monarchs in the Bay Area. Last winter, over 2,000 monarchs were likely reproducing in the Bay Area instead of overwintering further south. (Overwintering monarchs don’t reproduce until they begin moving north in the spring. Each generation travels further north.)

Such shifts in the sizes of breeding populations and habits of monarchs have happened before. In Australia in the 1970s, a monarch population crashed, but by changing reproductive habits the population didn’t disappear. One big question is if the breeding population is migrating north – this spring and now?

You can find a summary of James’ paper here, on the WSU Insider. If you want all the details and the full paper, you can find it here. If you want to track the latest news of monarch migrations, we recommend following James’ Facebook page, “Monarch Butterflies in the Pacific Northwest.”