American Copper

The American Copper is a small butterfly in the gossamer-wing family (Lycaenidae), closely related to the Small Copper of Europe and Asia, and by some classifications considered a subspecies of that widespread Old World species. It is common across much of the northeastern and north-central United States and adjacent Canada, thriving in weedy, disturbed habitats.

Its caterpillar host plants, sheep sorrel and curled dock, are themselves often considered common weeds of disturbed ground, which has allowed the American Copper to become one of the most frequently seen small butterflies in vacant lots, roadsides, and old fields rather than requiring pristine natural habitat.

The species' bright, fiery orange forewing coloring gives the genus Lycaena its common name of "coppers," a reference to the metallic-looking sheen of the wing scales.

• Forewings are bright orange above with a scattering of black spots and a dark border along the outer margin.
• Hindwings are mostly dusky gray-brown above with a bright orange band near the outer edge.
• Underside is paler, with the forewing retaining orange tones and black spots while the hindwing is pale gray with faint dark speckling.
• Small size and quick, low flight.
• Lookalikes: other copper species can appear similar but are generally more restricted in range or habitat; the combination of bright orange forewing with a gray hindwing bearing an orange band is a reliable field mark for this species in most of its eastern range.

Found across the northeastern and north-central United States and southern Canada, with additional populations in parts of the West. It favors open, disturbed habitats such as old fields, pastures, roadside verges, and vacant urban lots where its weedy host plants, sheep sorrel and curled dock, grow. Adults are active from late spring through fall, with several generations produced during the warmer months.

Adults fly low and fast over open ground, frequently basking with wings spread on bare soil, gravel, or low vegetation. They nectar at a variety of small flowers including clover and yarrow. Males are territorial, perching on prominent low vegetation and darting out to intercept passing insects, including other butterflies. Caterpillars feed on the leaves of sorrel and dock plants, and the species serves as a food source for birds and predatory insects at all life stages.

Eggs are laid singly on the leaves of sorrel or dock host plants. Caterpillars are green and slug-shaped, blending closely with the host foliage as they feed. Pupation occurs in a compact chrysalis near the base of the host plant. Multiple generations occur each year across most of the range (often two to three), with the species typically overwintering as a partially grown caterpillar or chrysalis depending on region.