Chico Wants You to Stop Stepping on These Caterpillars in Bidwell Park

If you have been hiking in Chico’s Bidwell Park lately, you may have noticed clusters of spiky, dark caterpillars crawling across the trails. Please do not step on them.

A new campaign is asking Bidwell Park visitors to protect the pipevine swallowtail caterpillar, a species that plays an important role in the park’s ecosystem but is frequently mistaken for a pest and crushed underfoot.

The caterpillars feed almost exclusively on California pipevine, a native plant that grows in the shaded, wooded areas of the park. As they eat the pipevine leaves, the caterpillars absorb toxic compounds that make them unpalatable to predators. That chemical defense carries over into adulthood, giving the adult butterflies protection from birds and other animals.

Pipevine swallowtail butterflies are one of the most striking species in Northern California. Adults have iridescent blue-black wings with bright orange spots on the underside, and they are a common sight in Bidwell Park during late spring and summer.

But the caterpillars are less glamorous. They are dark, spiky and tend to travel in groups across open trails, which is why they get stepped on so often. The campaign aims to educate hikers, runners and dog walkers about what they are looking at and why the caterpillars matter.

Bidwell Park is one of the largest municipal parks in the country, covering more than 3,600 acres along Big Chico Creek. The park supports a wide range of plant and animal species, and the pipevine swallowtail is one of its signature inhabitants.

Watch your step. These caterpillars are worth more alive than squished.