The monarch (Danaus plexippus), Karner blue (Lycaeides melissa samuelis), Quino checkerspot (Euphydryas editha quino), Saint Francis' satyr (Neonympha mitchellii francisci) and Oregon silverspot (Speyeria zerene hippolyta) butterflies are all important species for Defenders because of their imperiled status.

Each species is reliant on specific plants or plant families as hosts for their eggs and caterpillars. Their relationship with host plants may be disrupted as the world warms: the plants may most northward so that butterflies can’t find them; the butterflies may have to make longer, perilous migrations; and intensifying storms may blow butterflies off course. Pesticides harm species like butterflies even though they are not the target, and overuse of these chemicals destroys important habitats.

Human development is threatening migratory and non-migratory butterflies by fragmenting migration pathways and destroying habitats. Border barriers and other high walls can also block migrations because species like the Quino checkerspot only fly a few feet off the ground.

Defenders' Impact

Defenders works continually to ensure that Congress takes actions that maintain conservation funding for programs, such as the Farm Bill, that benefit landowners and wildlife like butterflies, while preserving environmental protections.

Defenders fights for proper consultation with the Fish and Wildlife and National Marine Fisheries Services to ensure that activities like pesticide application or development won’t further jeopardize imperiled species.

We are also opposing the proposed border wall that may harm butterflies; wall proposals directly target the Lower Rio Grande Valley National Wildlife Refuge in Texas, as well as Bentsen Rio Grande Valley State Park and the National Butterfly Center.


The greatest threats to butterflies are habitat change and loss due to residential, commercial and agricultural development. Climate change, widespread pesticide use, and invasive species are also threatening many species of butterflies, because of both direct impacts and indirect impacts on native host plants.

Protection Status
Endangered Species Act
IUCN Red List

The monarch's status is under review.

The Oregon silverspot is listed as threatened.

The Quino checkerspot, St. Francis' satyr and Karner blue butterflies are all listed as endangered.

The IUCN has designated the monarch migration a threatened phenomenon.

What You Can Do

Create healthy butterfly habitat in your backyard, at your school or business or even on your porch or balcony by planting native flowering plants. Don’t use pesticides on your plants!

Latin Name
Order Lepidoptera
The world’s smallest known species, the blue pygmy found in southern California, has a wingspan of just over half an inch. The largest species, New Guinea’s Queen Alexandra's birdwing, can measure up to 12 inches across.
The average lifespan for an adult butterfly is 20 to 40 days. Some species live no longer than three or four days; others may live up to six months.

The monarch is widely distributed across North America, from Central America northwards to southern Canada, and from the Atlantic to the Pacific coasts.
The Karner blue butterfly was found in a continuous band throughout its range but today is found in portions of New Hampshire, New York, Michigan, Wisconsin, Ohio, Indiana, and Minnesota.
The Quino checkerspot butterfly is found in a few counties in southern California and northern Mexico.
No populations of St. Francis’ satyr have been discovered outside of Department of Defense lands at Ft. Bragg, North Carolina.
The Oregon silverspot once thrived in coastal habitat in Oregon, Northern California and Washington, but today it is found at only four locations in Oregon.


Population numbers are generally unknown, but due to shrinking habitat and other threats, populations are threatened and declining.


Some species migrate to avoid adverse conditions. Most migrate relatively short distances, but monarchs migrate over 3000 miles. Monarchs can produce four generations in one summer. The first three generations will have life spans from two to six weeks and will continue moving north. During this time, they will mate and have the next generation that will continue the northward migration. The fourth generation is different and can live up to nine months. These are the butterflies that will migrate south for winter to either Mexico or southern California. Camouflage and chemical defense, where the butterfly has evolved to have toxic chemicals in its body, help defend butterflies from predators. While camouflaged species often look like bark or leaves, toxic butterflies are often brightly colored, and predators associate their bright color with the chemicals.


From egg to adult, butterflies undergo a series of physical transformations known as metamorphosis. After mating, the female butterfly lays her eggs on a caterpillar food or “host” plant. The eggs can hatch within a few days, or within months or even years, depending on whether conditions are right. Caterpillars shed their skin several times as they grow, and then form a chrysalis or pupa. Days, months or even years later, depending on the species, a fully developed winged adult emerges from the chrysalis and the cycle begins anew.


Butterflies rely on the nectar from flowering plants. Caterpillars of each species have their own preferences: monarch eat milkweed, Karner blue eat wild blue lupine, Quino checkerspot eat dwarf plantain, St. Francis’ satyr eat sedges and Oregon silverspot eat early blue violet.


Florida panther
Washington, DC

New App Tracks State-specific Endangered Species Protections

For more than 45 years, the U.S. federal government has played a critical roel in protecting endangered and threatened species through the Endangered Species Act (ESA).

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