WSU entomologist predicts low monarch population in the Pacific Northwest

As the western monarch population continues to struggle, some estimates have it declining over 80 percent compared to years prior. A Washington State University entomologist and butterfly specialist is painting a disappointing picture for the Pacific Northwest.

Dr. David James, of WSU’s Prosser campus said the few monarchs likely to be sighted in our region will be mainly in Eastern Washington and Idaho, and will likely be the offspring of monarchs who overwintered in Mexico, as opposed to California.

Monarchs are known for their seasonal migrations, which can be thousands of miles long.

James said that there have been no credible reports of new generation monarchs in Northern California or Oregon thus far, and that an annual census he has run since 2012 in Northern California over Memorial Day, yielded nothing. That survey was done in Northern California.

Despite prevalent milkweed, monarch caterpillar’s sole food source, there were no butterflies and no eggs. James said that in his eight years surveying the location, there have never been no monarchs.

In 2015 for example, James noted that there were 110 monarchs found.

James said the next two weeks will be critical for monarch migration to the Pacific Northwest, but that expected colder weather and an end to lengthening days, a cue for migration, will potentially prevent northward migration.

If you see a Monarch you are asked to photograph it and report it to your local butterfly organization, or to Dr. James. More on his contact information is here on the WSU Prosser website.

James said it is easy to mistake monarchs from a distance with Painted Ladies, a butterfly which is expected to be very prolific this year.

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