'It's magical' — Rhode Island still abuzz with dragonflies as Henri departs
NEW SHOREHAM, R.I. — Storm surges and power failures dominated much of the coverage of Tropical Storm Henri, but it was the appearance of thousands of dragonflies on Block Island after the storm passed that captivated naturalists and other enthusiasts.
“It’s magical. They’re still here,” said state Rep. Blake Filippi, the House minority leader, who lives on the island. “They’re like little jet fighters in the sky. They’re hard to snap.”
But whether the winged beauties emerged from the island’s wetlands and ponds, or were blown in by the storm during their migration south, remains a mystery.
Native, or blown off course?
Their abundance did not come as a surprise to Virginia “Ginger” Brown, the state’s preeminent dragonfly expert and author of “Dragonflies and Damselflies of Rhode Island.”
While Brown didn’t witness the influx firsthand, she said dragonflies are often on the move this time of year. She theorized that it was probably a combination of migratory species blown off course by the storm and those emerging from the water.
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Kim Gaffett, a naturalist with The Nature Conservancy on Block Island, reported that the dragonflies she has seen are yellowish-brown with bulging red eyes. Brown identified the species as wandering gliders, a highly migratory species known to travel long distances. It was the first time Brown had recorded the species on Block Island.
“That species is well known to wander over the ocean,” Brown said. It also remains in flight almost all the time, making them difficult to catch on camera or otherwise.
Gaffett surmised that changes in the temperature and barometric pressure brought on a massive hatch on the island, where dragonflies are always aplenty.
“This was a big hatch, no doubt about it, but it’s probably not because of the storm,” Gaffett said, adding, “It’s not unusual to have a large hatch of dragonflies.”
Still others on Block Island reported seeing green dragonflies, bolstering Brown’s belief that migration played a role.
August is prime time in the region for huge migrating swarms of common green darners, generally moving southwest along the coastline, Brown said in an email.
“Normally, there are thousands of dragonflies dispersing and migrating this time of year. Most of them are Common Green Darners (Anax junius), but there are also smaller numbers of several other species mixed in with these migrating groups,” Brown, of Barrington, said.
That species, named for its resemblance to a darning needle and distinct colors, are sturdy, strong-flying migratory dragonflies that are often found near water.
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'Enjoy the mystery'
“I’m guessing that the dragonflies that showed up on Block Island were migrants or dispersing individuals that came to shore behind the storm. They may have been ‘bottled up’ behind the storm, or simply carried landward by the storm,” Brown said, drawing a parallel with migratory birds.
Dragonflies are aquatic insects with voracious appetites. They commonly eat mosquitoes and midges, but will also devour butterflies, bees, flies and even each other, according to the Smithsonian. Agile insects, they often catch their prey midair. Little is known about their migration, but different species will swarm together by the hundreds to migrate and feed. They lay eggs in water.
“It’s exciting because it’s cool and they’re so many of them,” Gaffett said.
“Usually observation, the act of slowing down and taking notice – seeing, not just looking – is more important than ‘solving’ the many mysteries of nature,” Gaffett said. “Enjoy the mystery.”
Follow Katie Mulvaney on Twitter: @kmulvane.