WATCH: Thousands of Tree Swallows Create Stunning ‘Birdnado’ Over Massachusetts Refuge
A tornado appeared to take shape over a Massachusetts wildlife refuge this week. No storm warning was necessary; the swirling darkness was less cloud and more 100% birds.
On Sept. 14, thousands of tree swallows filled the sky above Parker River National Wildlife Refuge in Newburyport during their fall migration, creating a spectacle the U.S. Department of the Interior dubbed a “birdnado.”
The department shared video on Tuesday, starring an enormous flock gathering above the refuge before continuing south. In the video, the birds appear to stop in the area to rest and refuel on insects and berries during their journey.
“When enough swallows show up at once, migration starts looking a lot like Twister… the original… not the remake,” the department joked in its social media post.
A ‘Birdnado’ Is Actually An Annual Sight
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Birdnado incoming. 🌪️🐦
Thousands of tree swallows gather at Parker River National Wildlife Refuge during fall migration to rest and refuel on insects and berries before heading south.
When enough show up, it looks a lot like Twister… the original… not the remake. pic.twitter.com/drIE4UiIkc
— U.S. Department of the Interior (@Interior) September 14, 2026
The scale looks extraordinary, but tree swallows gathering at Parker River is anything but a freak occurrence.
The U.S. Fish and Wildlife Service describes their massing at the refuge as an annual phenomenon. During migration, the birds sometimes gather there by the tens of thousands while hunting insects or settling into their evening roosts.
Massachusetts is uniquely well suited to this phenomenon. Mass Audubon names the tree swallow as the state’s most abundant swallow and says huge flocks assemble along the coast during fall migration.
By July and August, hundreds can already be seen lining telephone wires near salt marshes and shorelines. Those numbers can increase exponentially quickly. But just how high do their numbers reach?
Tree Swallows Are Built For Life in A Crowd
If anyone is going to form a tornado of comrades, it’s the tree swallow. Tree swallows are highly social outside the breeding season. The Cornell Lab of Ornithology writes that migrating and wintering flocks can sometimes number in the hundreds of thousands.
Around sunset, the birds can gather into a dense cloud above a marsh or other roosting site, circling as more individuals gradually drop out of the sky to settle for the night. The result can look remarkably like a living tornado.
Usually, Eastern tree swallows migrate down the Atlantic coast toward wintering grounds in Florida and Central America, according to Cornell’s migration guide.
Parker River’s marshes provide one of the places where those traveling this great migration path can enjoy a brief respite.
