Monarch Butterflies in Wisconsin: Identification Guide and Best Places to Start

Monarchs favor open habitats with abundant milkweed and nectar sources. In Wisconsin, look for them in restored prairies, roadsides, and lakefront dunes. Specific hotspots include the Apostle Islands National Lakeshore, Horicon Marsh, and the extensive prairie restorations at the University of Wisconsin Arboretum. Backyard gardens with milkweed, coneflower, and goldenrod also reliably attract them.

Adult monarchs arrive in Wisconsin from late May through June, but the peak visibility window is late August to mid-September during their southward migration. Warm, sunny days with light wind offer the best odds. After cold fronts, they often congregate at nectar-rich spots. Early morning is good for seeing them roosting in trees before they warm up.

The monarch's bold orange wings with black veins and white dots on the edges are distinctive. The two key lookalikes in Wisconsin are the viceroy and the queen butterfly. The viceroy has a black line across the hindwing that monarchs lack. Queens are darker, with fewer black veins and white dots only near the wingtips. Monarchs also glide on a dihedral (wings raised in a V) pattern, while viceroys fly flat.

See our state animal guide for the next step.

Monarch caterpillars are unmistakable: bright yellow, black, and white striped bodies with a pair of black tentacles at the front and back. They are only found on milkweed plants. The eggs are tiny (1 mm), pale yellow-green, and laid singly on the underside of milkweed leaves. If you see a milkweed plant with chewed leaves, examine the undersides for eggs or small caterpillars.

Eastern monarchs, including those from Wisconsin, migrate to the oyamel fir forests in central Mexico. They travel up to 3,000 miles, often stopping along the Gulf Coast. Many of the monarchs you see in late summer are actually the fourth generation that will make the return trip. No individual completes the full round trip. This cycle fascinates many backyard observers.