New York Karner Blue Fact Sheet

This fact sheet provides background information on the Karner Blue butterfly.

What are the identifying characteristics of the Karner Blue?
With a wing span of just one inch, the Karner Blue is around the size of a stamp.  Like all butterflies, the Karner has two forewings and two hind wings. The male has a purplish-blue topside, and its wings are outlined in black. The female’s topside is darker blue with tones of brown and orange spots on its hind wings. White scales called fringe line the outer edges of both the males’ and females’ wings. The underside of the males and females is grayish with orange crescent shaped spots on both the forewings and hind wings.

What it the Karner Blue’s habitat?
Blue lupine, a wild pea plant, is critical to the survival of the Karner. It is the Karner caterpillar’s only known source of food. The Karner Blue lives in pine barrens which are dry areas where plants that don’t need a lot of water, such as lupine, grow well. 

What role do Karner Blues play in New York ecology?
Karner Blues are nectar feeders that pollinate wildflowers such as butterfly weed. 

What is the lifespan of the Karner Blue?
Like all butterflies the Karner Blue has four stages in its life cycle – (1) the egg, (2) the larva or caterpillar, (3) the pupa or chrysalis, and (4) the adult or butterfly. There are two life cycles per year: In May, the first group of butterfly larvae hatch from eggs that were laid on or near blue lupine the previous winter. The tiny caterpillars crawl up the lupine plants and begin feeding on the leaves. The larvae feed on the lupine for three to four weeks and then form into a chrysalis. They spend eight to eleven days as a pupae and then emerge as an adult butterflies in June. The Karner Blue usually lives in its adult form for five days but some have lived as long as thirteen days. The adult butterflies lay eggs on the lupine plant. The second group hatches sometime between late July and August, gorges on lupine, becomes butterflies, and lays eggs at the end of the summer. The eggs remain there through the winter. 

Who discovered the Karner Blue? Why is it called Karner?
Vladimir Nabokov, a famous writer, first identified the Karner Blue. It was named after the town of Karner where Vladimir first observed it.  

In which parts of the state does the Karner Blue live?
A long time ago there were so many Karners that they were described as clouds of blue. Now only a few small populations survive in the Pine Bush. The butterfly lives in other places besides the Pine Bush. There are spots of butterflies in Clifton Park, New York - about twenty miles north of the Pine Bush - and near the Saratoga Airport.  

In which parts of the country does the Karner Blue live?
The Karner Blue lives in New York, Michigan, Wisconsin, and Minnesota. It became extinct and then was reintroduced in New Hampshire, Indiana, and Ohio. It is now extinct in Maine, Massachusetts, Pennsylvania, and Illinois.

Why is the Karner Blue endangered?
The Karner Blue is endangered because its habitat has diminished tremendously. Specifically, land developers are destroying the Karner caterpillars’ only source of food the blue lupine. Also, putting out wildfires has hurt the lupine. In the past, fires burned away some of the lupine’s competitors and made it easier for it to grow back.    

How long has the Karner Blue been on the endangered species list?
The Karner Blue was listed as endangered in 1992.  

Since being protected by the Endangered Species Act, has the Karner Blue’s situation improved? Is the number of New York Karner Blues growing?
The status of Karner Blues in New Hampshire has improved since being protected by the Endangered Species Act. New York Karners, however, have not fared as well because their land developers continue to destroy their habitat.   

What specifically is New York doing to protect the Karner Blue? What groups are involved?
The Karner Blue Federal Recovery Plan has three priorities. In New York State, scientists are focusing on the first priority, which is “doing those things necessary to prevent extinction of or the irreversible decline of the species”. This means (1) counting and tracking populations, (2) protecting their current habitat, and (3) expanding their potential habitat by buying land and setting it aside.
New York is trying to protect the Karner Blue’s habitat by setting aside land in the Albany Pine Bush area. The New York State’s Department of Environmental Conservation, the Town of Wilton, New York, Save the Pine Bush, The Nature Conservancy, the Albany Pine Bush Preserve Commission, the Wilton Wildlife Preserve and Park and the Northeast Region of the U.S. Fish and Wildlife Service are working together to protect the Karner Blue’s habitat.