Goodbye butterflies? Survey reflects dwindling Westchester habitat

A hackberry emperor butterfly. A great spangled fritillary. A hackberry emperor butterfly. CONTRIBUTED PHOTOS 

By BRIAN KLUEPFEL

Butterflies come in a variety of sizes and colors, one more stunning than the next. Bearing regal names like monarchs and emperors, viceroys and admirals, this order of insects flits about the open fields of Westchester, acting as pollinators, as well as food sources for larger species.

Moving quickly in patterns difficult to discern, butterflies are indeed hard to glimpse, and viewing them is getting harder each year. According to annual surveys conducted by the North American Butterfly Association, numbers of individuals and of species (more than 600 species currently exist in the U.S.) are being reduced each year, locally and nationally.

The most recent endeavor to count and account for butterflies was led by NABA’s new Westchester chapter on July 5, in a 15-mile-diameter circle bounded by North Salem, Pound Ridge, Mount Kisco/Greenwich, and Teatown Lake Reservation. Eight groups spent the day in search of Lepidoptera (the order comprising both butterflies and moths), an early summer tradition dating back four decades in Westchester.

Charlie Roberto, a retired New York City Fire Department captain and experienced naturalist, organized the NABA chapter’s efforts on this bright July day, yet his outlook was less than sunny. 

“Nobody’s doing anything to improve their (butterflies) chance of survival,” Roberto said. He spoke of butterfly-friendly plant species which once thrived. “Before there were big stands of milkweed along Route 119, by Rockefeller Park Preserve. Now it’s mostly mugwort and vines,” he continued. 

“The porcelain berry (native to China and Japan) has increased tenfold in the last 10 years,” he continued, “ We really need to control the invasives.” 

While porcelain berries tend to monoculture, blocking out native trees and shrubs, Roberto also noted the loss of some local trees to disease, such as beeches.  

Jeff Glassberg, president/founder of NABA and a former Chappaqua resident, also lamented the latest statistics. 

“The number of butterflies has greatly decreased” since the first count, he said. “The count routinely sees about half the number of individuals seen in the 1980s and some species, such as meadow fritillaries, are completely gone.” 

The halcyon days of the northern Westchester count — such as 1989s amazing 300 mourning cloaks, and historic counts for 14 species — are seemingly over,” Glassberg said.

Indeed, according to experts, over the past 20 years, the U.S. has lost 22 percent of its butterflies; in Westchester, the numbers are grimmer still, with a reported decline of 50 percent. 

In a recent talk at Teatown Reservation, Glassberg enumerated the butterfly’s challenges to survival. He noted that 98 percent of the country’s original tallgrass prairie is gone. He also cited the growing use of neonic pesticides, closely linked to bee and bird population decline, as well as a warming climate and the introduction of invasives like kudzu and Japanese stiltgrass.

However, in some instances, butterflies have adapted: the northern pearly eye now uses the stiltgrass to breed. And the dusky wing became very prolific on non-native plants.

John Hannan, president of Bedford Audubon, came away from the count impressed with the collective knowledge. 

“It was great to be with experts and beginners identifying multiple species across our Bedford Audubon Bylane Farm,” he said. “It confirmed how much biodiversity can exist when landowners provide wildlife with native plantings and a pesticide-free environment.”

He underlined the last point. 

“For the health of your family, pets and butterflies avoid using pesticides and chemical fertilizers that poison butterflies and are often cancerous to humans and pets,” Hannan said.

This reporter took part in the butterfly count as a member of a trio comprising Anne Swaim, executive director of Saw Mill River Audubon, and Justine Davenport of Croton. In addition to finding out just how quickly butterflies move (very), our bit of citizen science echoed the statements of Roberto and Glassberg. In the Mount Kisco swamp we explored, formerly a rich wetland habitat, roadsides had been sprayed with herbicide in a solid 10-foot swath on either side, we saw nary a butterfly or living thing.

At the same time, uncontrolled growth can be overwhelmingly negative, too. 

“Glazier Arboretum (in Chappaqua) used to have large populations of a wide variety of butterfly species — great spangled fritillaries, meadow fritillaries, black dashes,” Glassberg said. “Now there is literally nothing there due to unchecked successional plant growth and invasive plant species.”

Despite a lack of success, we did see some beautiful winged creatures: three cabbage whites, three orange sulphurs, four summer Azures, and a whopping 15 great spangled fritillaries — a total of 14 species in all. If our tally was nothing like past glories, it certainly was enough to inspire a couple of first-timers to return. Forty-seven different species were recorded by all groups.

The day’s efforts ended at a Mount Kisco’s restaurant, with the counting contingent feeling content at having done their best for the scientific record. 

Amidst the low numbers, some glimmers of hope remained. Roberto saw an American snout and a hackberry emperor near a hackberry tree at Teatown Reservation. These were the only individuals of the species seen, yet evidence that they’re still around. 

More than hope will be required to restore butterflies to their former majesty, but a small group remains determined to fight for their survival in an uncertain world.