Our State of the Butterflies

Butterflies are in trouble.

That’s the conclusion of the first-ever comprehensive report on the fate of butterflies, released last year by the Xerces Society for Invertebrate Conservation and led by Cheryl Schultz, a conservation biologist at Washington State University.

The report looked at monitoring data for 342 butterfly species⁠—about half of known US species⁠—and found that butterfly numbers declined 22% from 2000 to 2020. That means someone who counted 100 individual butterflies in 2000 would only see 78 butterflies during the same count in 2020.

“In many ways, it’s depressing because there are so many butterflies tanking,” says Schultz. “But there are things we can do … and, collectively, we can make a big difference.”

It turns out that butterfly enthusiasts in the Pacific Northwest may be in a good position to protect our fluttery neighbors. The numbers for Pacific Northwest butterflies dropped just 2.7%, though about 25% of species with sufficient monitoring data showed significant declines. That’s stark⁠—but the declines here may be less severe than in other parts of the country. (View which PNW butterfies increased or decreased in this PDF infographic.)

Regional experts are already using the data to drive conservation decisions.

“What we’re trying to do in Washington is incorporate those species into our priorities,” says Ross Winton of the Washington Department of Fish and Wildlife, referencing the recent Washington State Wildlife Action Plan. “Just like we need systematic monitoring, we need a systematic approach to identifying our conservation needs.”

We know butterflies are disappearing because of habitat loss, pesticide use, and climate stress. Here’s what we can do now to help Washington butterflies.

 

Learn more about butterflies. Butterflies need three things: nectar plants to feed on, host plants for their young, and clean habitats with limited exposure to pesticides.

 

Plant nectar plants that bloom throughout spring, summer, and fall. Adult butterflies feed on flower nectar whenever they are in flight. Install native plants when you can⁠—but don’t pull exotic or invasive flowering plants without replacing them with another butterfly-friendly plant.

 

Provide host plants for caterpillars. Butterflies lay eggs on or near plants suitable for their caterpillars to eat. Those host plants may be different from their nectar plants. Monarch caterpillars famously only chow down on milkweed. But adult monarchs sip nectar from a variety of flowers.

Support wild spaces. While some butterflies are strong fliers, many are habitat specialists that stick close to home. Restoring wild patches so they are close enough for butterflies to fly from patch to patch will allow butterflies to rest and refuel as they lay eggs, seek mates, drink nectar, and expand their populations. Many butterflies overwinter as eggs or caterpillars in dense vegetation or leaf litter.

 

Reduce pesticides. Reconsider using these at home. Instead, choose nonchemical techniques to manage pests. Avoid using chemical controls on flowering weeds or in wild spaces like bike paths or roadsides that may connect natural habitats. Speak up for butterflies in your community spaces.

 

Look for butterflies around you. You may spot important butterflies when you’re gardening, fishing, hunting, or walking your dog. Snap photos and identify what you see using apps like Seek. Upload your observations to iNaturalist to contribute to the body of scientific knowledge. Last year, a photo uploaded by a new user alerted Washington scientists to a population of Taylor’s checkerspot on the Olympic Peninsula. Now they can monitor those endangered butterflies.

 

Butterflies are beloved. They help pollinate our wildflowers and crops. They make great meals for birds and other animals. And they’re environmental sentinels, informing us about the health of our ecosystems.