Potential impact of wind farms on monarch butterflies understudied, experts say

The prospect of thousands of offshore wind turbines spinning in the waters between New York and New Jersey may have unintended consequences for threatened monarch butterflies that migrate from Long Island beaches each fall, scientists and conservationists say.

A recent draft environmental impact study of the impact of offshore wind turbines in the New York Bight — the ocean waters off New York and New Jersey — made only brief and passing mention of the monarchs, which congregate on South Shore beaches as part of their annual fall southern migration.

The draft environmental review by the federal Bureau of Ocean Energy Management precedes the next wave of offshore wind turbines planned for the bight, where Empire Wind 1 could see turbines spinning off Jones Beach in two years. Developer Equinor recently stalled plans for a second wave of turbines called Empire 2. But five other projects are planned for tens of thousands of acres of ocean, some just off the coast of New Jersey.

In a message in response to Newsday questions, BOEM spokesman Lissa Eng downplayed the potential impact to the butterflies, which are listed as a “candidate” for an endangered species act classification.

“Monarchs are unlikely to be found offshore as they generally prefer onshore and coast habitats in the geographic analysis area” being reviewed by the federal agency, Eng said. “Although it is possible that some may fly offshore during fall migration, most will migrate overland toward Mexico feeding on the abundant nectar resources and sheltering from bad weather along the way.”

But several experts said the federal bureau is dead wrong about the migratory patterns of monarchs, noting that butterflies fly over bodies of water to get to Long Island and proceed southward over the water all along the coast.

'Important migratory corridor'

Information from the Fire Island National Seashore discusses the fall migration specifically, and includes a video of monarchs flying over the ocean dunes.

Fire Island is “an important migratory corridor” for birds and insects, the park service notes, and monarchs “can be seen here during fall migration” when “thousands of these delicate insects stop to rest and feed on Fire Island as they make their way south for the winter." 

Those who study the monarchs say the impact of turbines could be large, and even the U.S. Fish & Wildlife Service says studies of the migratory patterns against turbine placement are lacking.

“My biggest concern with all of this is that we will likely never know the true impact, since any monarch that perishes from these [turbines] will simply disappear in the waves,” said Andy Davis, assistant research scientist for the University of Georgia's Odum School of Ecology, who studies monarchs and their migratory habits.

The number of potentially impacted monarchs is “probably in the order of hundreds of thousands,” Davis said in an email, though he noted that monarchs migrate at different heights “in any given day depending on the weather conditions. On some days they are way higher than these turbines. Others, they are flying closer to the water surface.”

Equinor, which is building the Empire Wind project off Jones Beach, said that because the project’s construction and operation plan was submitted “before the Monarch butterfly was designated as endangered, it was not an official part of” federal construction and operating filings.

However, Equinor spokesman David Schoetz said BOEM “did informally consult with U.S. Fish and Wildlife Service on potential land impacts and found that the proposed action is not likely to jeopardize the continued existence of the Monarch butterfly.” The statement doesn’t address impacts over the ocean.

Dangers extend past turbines

Ecologist Carl Safina, who holds the endowed chair for nature and humanity at Stony Brook University, said the potential dangers to migrating wildlife from turbines extend well beyond monarchs.

“I view the prospect of thousands of spinning blades off our coast as a nightmare for flying migrants of all kinds: butterflies, birds, bats,” he said. “The entire region is wildlife habitat, and this coastal corridor is a major flyway and migration route for animals above and below the surface.”

Safina said energy planners should focus instead on widespread installation of solar panels on highways, parking lots and warehouse roofs rather than “this plan for industrializing the wild ocean with spinning blades while enriching energy monopolies and multinational corporations … It’s not just the butterflies that will pay for all that.”

But Karen Oberhauser, a monarch butterfly expert at the University of Wisconsin-Madison, where she is a professor and director of the school's arboretum, said that while there “could be interactions with some monarchs, for sure,” she added that "the benefits of the carbon emissions that could be eliminated by replacing some fossil fuels would outweigh this cost.”

Oberhauser said that “while some monarchs do stray away from land, perhaps blown by the wind, they stay over land for the most part.”

Mara Koenig, spokeswoman for the U.S. Fish & Wildlife Service, acknowledged that the impact of turbines on monarchs is an “understudied topic” that “certainly merits future study.” For now, however, the service said the “best available information does not indicate that monarchs are likely to be found migrating offshore, as they generally prefer onshore or coastal habitats.”

She noted that there “are instances of monarchs crossing water, but it is usually when they are funneled in a peninsula and heading to another landmass, such as Cape May, New Jersey,” the apparent destination of the fall migration from Long Island. Koenig also noted that migrants “can fly quite high, potentially above where wind turbines have an impact.”

Alena Waters, a member of Nassau-based at Sea Life Conservation, an environmental group, said large numbers of monarchs known to migrate from the area around the west end of Jones Beach saw their habitat disrupted by the removal of goldenrod plants during the “cleanup” for the Energy Center in 2019..

While monarchs are “known to find the shortest path over bodies of water” and the shape of the Long Island and New Jersey coastlines make the bight “the shortest path,” she acknowledged she didn’t know how much of a shortcut they take or how far over the ocean they travel.

But Walters remembers the September migrations as a “magical experience.”

“There would be so many monarchs on the goldenrod plants that the plants themselves were not recognizable,” she said, “and there were so many butterflies in the air surrounding me, paying me no mind, that it truly felt like a magical experience.”

By Mark Harrington

mark.harrington@newsday.comMHarringtonNews

Mark Harrington, a Newsday reporter since 1999, covers energy, wineries, Indian affairs and fisheries.