More than 1,000 captive-bred Karner blue butterflies, released as chrysalises and emerging as adult butterflies, have nearly doubled the population of the endangered species in the Albany Pine Bush Preserve.
It is the latest in years of habitat restoration efforts by the Albany Pine Bush Commission.
“It was much more successful than we anticipated,” said Neil Gifford, the preserve’s conservation director, who supervised the project.
The effort to boost the butterfly population in the preserve began in May, when 20 wild female butterflies from the preserve were brought to breeding facilities at New Hampshire Fish and Game Department’s Concord facility and at Guilderland’s Farnsworth Middle School. Before being released back into the preserve, the females laid about 3,000 eggs.
About 1,700 transformed into tiny, hard-shelled chrysalises and in the second week of July, about 1,000 were placed into two separate areas of the preserve that had been restored and where there is enough blue lupine and wildflowers for adult butterflies to nectar on, giving them a good chance of survival.
The chrysalis is the easiest to handle stage of development and because they are in hard shells, it makes it easier to transport them. There’s also an advantage releasing chrysalises because they are more likely to stay in a particular habitat than an adult butterfly.
“We are monitoring the nets and walking the sites to find and locate adult butterflies. We know lots and lots of butterflies emerged,” Gifford said.
Karner blue butterflies don’t usually fly more than 200 yards in their 7-to-14-day lifespan, and the captive breeding project is being used to accelerate the population of nearly 200 acres of restored habitat and help the recovery of the Karner blue.
“It’s important to recognize that it takes time to restore ecosystems and their associated rare species,” said David Stilwell, field supervisor of the U.S. Fish and Wildlife Service’s state field office.
The program of breeding the butterflies in captivity provides a rare opportunity to watch the butterflies closely. The preserve commission knows how many chrysalises were released, allowing it to monitor the species.
Captive breeding hadn’t been done before in the Albany Pine Bush Preserve because there was not enough suitable habitat.
“It’s the culmination of habitat management,” Gifford said. “The sites had been infested with invasive plants. Here we have gotten rid of invasive species, like black locust, and planted the sites with native plants that are capable of supporting populations of Karner blue butterflies.”
Gifford first learned about the captive-bred butterflies a couple years ago during a conference in Indiana, where a recovery team was trying to reintroduce Karner blues that had gone extinct in that state. The Albany Pine Bush Preserve began working with the Indiana chapter of the Nature Conservancy, the New York state Department of Environmental Conservation’s Endangered Species Unit and the New Hampshire Fish and Game Department, all of which shared the goal of trying to reintroduce the Karner blue or increase its population.
The New Hampshire Fish and Game Department wanted to restore the species in its Concord Preserve, which is similar to the Albany Pine Bush Preserve. In the end, the Concord Preserve kept 25 percent of the chrysalis-stage butterflies it bred and the Albany Pine Bush Preserve got 75 percent.
The adult Karner blue is an endangered species first identified in the 1900s by novelist Vladimir Nabokov, who wrote “Lolita.” In the early 1900s, there were millions of Karner blues in the Pine Bush, and as recently as the 1970s, the population was estimated at between 10,000 and 100,000.
The commission has a 20-year recovery goal for a population of 27,000 butterflies, which would guarantee it could never fall below the recovery threshold based on the endangered species act.
The Albany Pine Bush Preserve is an inland pine barren system, and the commission was created in 1988 by the state Legislature to protect and manage the preserve.