It’s just after sundown in the deep, evergreen forest of the Albany Pine Bush Preserve outside Albany, New York, a time when rarely seen creatures emerge from the shadows. Somewhere in the late October night, an owl calls…and calls. It sounds like a saw being sharpened on a whetstone.
Flashlights winking, a team of researchers winds its way through the pitch pine–scrub oak barrens of the Albany Pine Bush Preserve’s 2.6-mile-long Yellow Trail. Amanda Dillon, a biologist at the preserve, points to a 36-foot-long fine net, called a mist net, strung between steel poles. A tiny northern saw-whet owl blinks at us; it’s caught in the netting.
To reach the pine bush, the owl made its way over a gauntlet of crisscrossing highways, suburban neighborhoods, industrial parks, and railroad tracks. The 5-square-mile preserve is, however improbably, one of the largest of 20 inland pine barrens left in the world and, scientists say, may be the best remaining example of this ecosystem.
Gift of the Glaciers
To understand the special qualities of this landscape, one has to start from the ground up, and events from the last ice age. As the Wisconsin glacier melted and retreated from the region, its snowmelt formed a glacial lake, and in the process deposited a massive delta of small rocks and sand. As noted by Jeffrey Barnes in Natural History of the Albany Pine Bush, this glacial lake extended north 50 miles from today’s city of Albany to modern Glens Falls, New York. About 12,000 years ago, the lake began to drain, leaving the sand exposed to air. “The remains of the ancient pine bush sand delta cover approximately 40 square miles,” wrote Barnes. Wind shaped the landscape, blowing sand into parabolic, longitudinal, and complex dunes 100 to 2,000 feet long. Over time, plants moved in and stabilized the dunes. Now “the dunes appear as open, rolling slopes dotted with pitch pine and carpeted with numerous understory plants,” Barnes stated.
These sandy, well-drained soils support a rare combination of frequently burned forests and shrublands. Pitch pine and scrub oak are common tree species, and rare plant species thrive in the sandy soil. Here, life pokes up its head in surprising ways. In June 2021, Jesse Hoffman, preserve steward and botanist at the Albany Pine Bush, discovered a rare plant that hadn’t been seen in the area since the Roaring ’20s – 1923, to be exact. The state endangered Virginia marbleseed (Lithospermum virginianum) isn’t showy, Hoffman says, “but it definitely has a certain charm. The spiraling flower buds look unusual and make the plant stand out.” The name marbleseed comes from the hard, shiny, white seeds the plant produces; they resemble the stone.
“The nature of rare plants is that you almost never locate them,” says Hoffman. “To have found a state endangered species that hadn’t been seen in 100 years is just amazing.”
The preserve is also an Important Bird Area (IBA), an international designation that identifies its habitat as globally important to bird conservation. The National Audubon Society leads the effort to identify, monitor, and protect IBAs in the United States. The Albany Pine Bush Preserve is one of some 2,758 IBAs covering 417 million acres of public and private lands in the United States. The pine bush hosts typical young-forest, shrubland birds such as eastern towhees and chestnut-sided warblers, but visitors also may catch a glimpse of prairie warblers, which are absent in much of New York, and for which the pine barrens provide critical habitat. During fall migration, black-throated blue warblers, Swainson’s thrushes, bobolinks, rusty blackbirds, American pipits, and other avian visitors – including northern saw-whet owls – have been recorded.
The federally and state endangered Karner blue butterfly is one of the preserve’s most celebrated species, and a symbol of its biodiversity. Decades ago, the tiny butterfly’s declining numbers mobilized conservationists and state and local officials to protect the pine bush. In 1988, New York Environmental Conservation Law Article 46 created the Albany Pine Bush Preserve. In 2014, the Albany Pine Bush Preserve was designated a U.S. National Natural Landmark.
The Karner blue was instrumental in preserving the pine bush for chestnut-sided warblers, lupines, and countless other species that live in this ecosystem. But butterfly and owl, warbler and lupine face continued challenges. Development on all sides is ever encroaching, from auto repair shops to pizza parlors to the industrial parks that encircle the nearby Crossgates Mall. In the center is the Albany Pine Bush Preserve, a testament to nature’s ability to thrive, even in the midst of rush-hour traffic and honking horns.
Diminutive Dwellers of the Pine Bush
Summer has come to the coniferous forests of northern New York and New England, and northern saw-whet owls are busy raising young in tree cavities, abandoned woodpecker holes, and artificial nest boxes. The young leave the nest when they’re four to five weeks old, then remain together near the site and are fed by their parents, mostly by the male owls, for another four weeks. Time at the nest site passes quickly, however. As late summer arrives, and with it, hints of autumn’s changing winds, the first saw-whets will begin to make their way south.
Among the continent’s smallest owls, saw-whet owls use the Albany Pine Bush as a stopover point in their autumn journeys south to the mid-latitudes of North America. They tend to migrate when the moon is less than full, taking advantage of the dark to avoid predators such as great horned owls. Since 2016, Dillon and her colleagues have been studying the owls’ habitat preferences while they’re in the neighborhood resting up. Scrubby pine forest is a saw-whet favorite.
The continuous owl calls in the woods – recordings of saw-whet owl “hoots” concealed beneath the mist nets – bring in the owls. In the darkness, even sharp owl eyes don’t see the nets until it’s too late. Once trapped, the owls are banded with a U.S. Fish & Wildlife Service numbered metal ring placed on one leg. The band allows researchers to track the birds’ movements if they’re re-trapped or found injured or dead.
During each night’s net-checks, owls are carefully extricated from the mesh and then carried to “processing areas” where they’re weighed, the length of their wings is recorded, and they’re banded. At the preserve, that takes place just inside the rear entrance of the visitor center, called the Discovery Center.
Within 20 minutes, the researchers complete their checklist and are back out in the pitch-dark. Owl number one of the night is all-systems-go, flapping its wings as researcher Dylan Chorny carefully holds its talons. “Everyone ready?” he asks. For this northern saw-whet owl, the answer is definitely yes. Chorny opens his hand, and the owl flitters to a nearby scrub oak tree. There it lands, shakes once to settle its ruffled feathers, and takes off into the blackness. By sunrise it may be miles away, winging its way south of these piney woods.
Fire Preserves Pine Bush Habitat
Habitat loss from development surrounding the Albany Pine Bush Preserve is on a par with habitat destruction due to a lack of fires, says Neil Gifford, the preserve’s conservation director. “The pine bush needs fire to maintain the open plant communities found here,” he explains. “Fire prevents the succession of vegetation that would otherwise lead to a closed forest.”
The flames destroy fire-intolerant species and burn accumulated organic matter, discouraging plants that need more fertile soils. Those species would otherwise replace native plants that thrive in fire-prone, low-nutrient conditions. The blazes also stimulate the sprouting of fire-tolerant species, which can then grow without competition.
But fire isn’t welcome in an area that’s chock-a-block with homes and businesses. To counter a recent history of fire suppression, Albany Pine Bush crews deliberately set and control fires to maintain the pitch pine–scrub oak barrens. (See Spring 2022 Northern Woodlands for a perspective from the coastal pine-oak barrens of Massachusetts.)
Thanks to this periodic fire regime, the Albany Pine Bush landscape turns bright blue once each year: in late May and early June, purple-blue lupine flowers burst into bloom, and Karner blue butterflies flit from lupine to lupine.
In the preserve, wild lupine blooms in open areas of pitch pine–scrub oak. During the past 15 to 20 years, however, the number and size of lupine patches have declined to one-tenth of what they once were. Fire suppression and land development are likely to blame, researchers believe. On a June morning, Gifford points to a valley where lupine flowers cover the hillsides. “We did a controlled burn here this spring, and in a short time, look at how the plants have regrown,” he says. Lupines dot the landscape as far as the eye can see.
That’s good news for the pine bush’s butterflies, especially its Karner blues, which once floated across the Albany region by the millions. Wild lupine is the only food of the Karner blue’s caterpillar; the plant’s decline is the main reason for the butterfly’s dwindling numbers.
With help from human hands, the Karner blue butterfly is returning to many of its former Albany Pine Bush haunts, and can now be found at some 60 sites covering more than 700 acres. In May 2021, biologists captured 24 adult Karner blues; the butterflies’ eggs were raised to chrysalises. By July, they had emerged as adults and were released at new sites that were too isolated for them to find on their own, says Gifford. “These colonies represent the return of this butterfly to locations where it was once abundant.”
The Butterflies of Winter
Novelist and lepidopterist Vladimir Nabokov of the Harvard University Museum of Comparative Zoology first described the butterfly in 1943, based on a male Albany Pine Bush specimen. His novel Pnin, published in 1957, compared the butterflies to “blue snowflakes.”
The snow crystal description was apt. In early summer, Karner blues lay eggs low on lupine stalks beneath what would be the usual winter snowline. Come late November, the eggs will be covered by a blanket of snow and will remain there until the following spring.
Karner blue butterflies have two generations each year. In April, the first caterpillars hatch from eggs that were laid the previous year (the eggs that overwintered). By mid-May, the caterpillars pupate. Adult butterflies emerge from their chrysalises by the end of May or early June. These adults mate, laying their eggs in June. The eggs hatch in about a week and the caterpillars feed for about three weeks. They then pupate and the summer’s second generation of adult butterflies appears in July. Then these adults mate and lay the eggs that will not hatch until the following spring.
Eggs laid in July spend the following winter under the snow, insulated from the cold air. Although many Albany Pine Bush Preserve species benefit from access to the subnivean zone, the future of the Karner blue, in particular, is dependent on reliable winter conditions.
“The southern boundary of [the Karner’s] distribution may coincide with the southern limit of an 80- to 120-day continuous winter snow cover necessary to prevent freezing, desiccation, or premature hatching of overwintering eggs,” explained Robert Dirig of Cornell University in Karner Blue Butterfly: A Symbol of a Vanishing Landscape. Those words were written in 1994, more than a quarter-century ago. Now northeastern states are among the fastest warming places in the United States.
On an early March day, the Pine Bush’s sands are dotted with snow patches that are melting fast. Near the ground on a lupine twig lie the likely remains of a Karner blue egg. From the shriveled casing, it’s clear that no butterfly will emerge to flit across the barrens in spring. “Karners usually lay their eggs 6 to 8 inches above ground,” says Gifford. “At that height in a ‘normal’ winter, they’d be covered with snow all season, critical to the developing butterflies.”
Dillon adds that in recent years the preserve “doesn’t seem to be holding a good snowpack.” That’s bad news for Karner blue butterfly eggs, she says. They’re at risk if they don’t have a constant snowpack to buffer them against winter temperatures.
According to the U.S. National Weather Service, the winter of 2020–21 brought 54.6 inches of snow to the Albany area. The winter of 2019-20 saw 49.7 inches. Compare these to the 30-year average of 59 inches (and a record 112.5 inches in the winter of 1970-71).
Scientists hope Albany’s Karner blues don’t go the way of those that lived at Indiana Dunes National Park along Lake Michigan, where Karner blues are now locally extinct. Winters with warmer temperatures and little snow are likely to blame.
The Albany Pine Bush’s Karner blues might have met the same fate – and could still. “This tiny blue insect could easily have slipped unnoticed into extinction,” Barnes wrote, “but it is now a symbol of endangered species, taking rank with the likes of the wolf and the peregrine falcon.” A century hence, will Karner blue butterflies still take to the skies above a gift of the glaciers?
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