The quarter-sized Karner blue butterfly population in the Wilton Wildlife Preserve and Park is reaching its peak for the summer.
The second brood of the endangered Karner blue is out in good numbers this year, said Sarah Clarkin, the park and preserve’s executive director.
Since the park was started in 1996 almost 2,000 acres on the east side of the Northway, including open land ideal for the Karner blue butterfly, have been protected.
Clarkin said the Karner blue, which is on both the state and federal endangered species lists, is not thriving. “It’s still precarious,” she said. “But we are gaining ground.”
She said the park and preserve has restored more than 120 acres to Karner blue habitat, which means open land with the blue lupine wildflowers. In some areas trees have been removed so the blue lupine can grow in the sandy soil.
Each spring, volunteers help Clarkin and one or two interns plant the blue lupine and various wildflower seeds that provide nectar.
The park and preserve will host the season’s last Karner blue butterfly walk at 10 a.m. today at the park’s Old Gick Farm location on Route 50.
Taryn Sudol, a park intern from the University of Florida, will lead the walk and discuss the insect’s life cycle, its habitat and the threats confronting its survival. The walk is free and just under one mile across rolling terrain. The preserve and park held earlier walks when the butterfly’s first brood hatched in mid-to-late May.
Karner blue butterflies can also be found in Albany’s Pine Bush, near the Saratoga County Airport in Milton, and along Route 9 on Saratoga Spa State Park property.
But the Wilton preserve and park is where the largest numbers of butterfly colonies are located.
“This is the largest population in the East,” Clarkin said. At one time there was a large Karner blue population near Saratoga County Airport, but “the numbers there have really declined.”
Clarkin does not have exact numbers for the butterfly population, but a new methodology is being used this year by park interns that will provide an accurate estimate for the preserve and park.
Wilton is part of geologic area that extends from Glens Falls to Albany. After the retreat of Ice Age glaciers between 10,000 and 20,000 years ago this region was the basin of a large lake called Glacial Lake Albany. Rivers emptied into this long-gone lake and deposited sand and silt, making the soil very sandy after the lake dried up.
Prevailing winds blew these sandy soils into dunes. The blue lupine wild flower thrives in the open, sandy soils. The Karner blue butterfly lays its eggs in the blue lupine and the butterfly’s caterpillar stage eats the plant after hatching.
One of the goals of the Wilton Wildlife Preserve and Park is to protect the Karner blue. For more information on the preserve and park see: www.wiltonpreserve.org or by phone 450-0321.