Amazing: Tiny Birds Fly Without Landing for Three Days

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Warblers that weigh about as much as a stack of 12 business cards fly thousands of miles across the Atlantic during their fall .

Imagine a journey that requires you to first pack on the pounds, then get rid of your intestines, and finally to forgo eating and sleeping for three days. For the blackpoll , such a feat is called their fall migration.

Barely half an ounce (12 grams), these tiny birds fly from northeastern Canada to South America every fall. But no one knew what path they took.


Blackpoll warblers, like this male, may be tiny, but they’re able to haul themselves across the Atlantic without stopping during their fall migration – Photograph by Robert Royse

It turns out the warblers fly nonstop over the Atlantic Ocean, researchers report March 31 in the journal Biology Letters. (Learn about the world’s longest migration.)

They absorb organs they don’t need for their flight, like their intestines – Ecologist Bill DeLuca

Ecologists affixed lightweight tracking devices to five blackpoll warblers during the fall 2013 migration to discover the animals’ overwater route.

The warblers fuel up on fat for the journey, going from 0.4 ounces (12 grams) to 0.6 ounces (16 grams), says lead study author Bill Deluca, an ecologist at the University of Massachusetts, Amherst. Some overachievers double in weight. “Basically, they’re these little meatballs with wings,” he says.

Picture of Breeding male blackpoll warbler with geolocator attached. Mt. Mansfield, VT
A lightweight tracking device called a geolocator allowed researchers to track flight paths – Photograph by Vermont Center for Ecostudies

Then they absorb internal organs they won’t need for the trip, like their intestines, to reduce excess weight, Deluca says. Reduced to fat, feathers, and muscle, the birds depart, taking advantage of trade winds for their journey south.

The warblers can’t catch these winds on their way back, so they take an overland route in the spring, Deluca explains.

The Big Picture

Researchers aren’t sure why the warblers fly south over the ocean but return over land. It could be a remnant of ancient migratory pathways, Deluca says, or it could actually be safer.

Basically, they’re these little meatballs with wings – Ecologist Bill DeLuca

Flying over land, birds have to contend with predators and collisions with buildings or cars.

Migrators from birds to butterflies face a gauntlet of danger. Larger birds that can carry more fuel travel farther—such as the Arctic tern, which hopscotches from Greenland to Antarctica and back with stops in Africa, South America, and the Arctic. (Read about threats facing other migratory birds.)

Knowing exactly where birds like the blackpoll warbler go is crucial to their conservation, Deluca adds. “This species is probably one of the most common warblers in North America,” he explains, but “it’s also one of the fastest declining species.”

What’s Next

Researchers don’t know why the birds are disappearing and whether the problem lies in North or South America. So Deluca and colleagues hope to collaborate with South American researchers to figure out where these birds spend their time and what threats they face.

This article was first published by National Geographic on 31 Mar 2015.


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Cat Vincent
Cat Vincent

Stunning article, I am continually astounded and humbled to learn about the mind boggling events that occur in our natural world, 'There are more things in Heaven and Earth, Horatio…….!'. Thank you for my ongoing and never to end education.

Susan Lee

Thank you for this article! I've occasionally seen these not-really-chickadees-just-chickadee-resembling birds around my grounds, though briefly. It is likely just that the Florida Northwest Panhandle area where I am, near the Gulf Coast is a brief rest-refuel point on the migratory journeys of these birds. Heaven knows that Florida has plenty of bugs for every bug-eating species of critter!

Linda French
Linda French

Truly a amazing article on this little bird. I am a amateur bird watcher and I find it amazing what they are capable of. I continue to learn I am in North Eastern Canada and get to see a lot of real interesting birds that migrate through my region.

Ralph Hobbs

Widespread use of neonicotinoid insecticides in on arable land in N America probably won't be helping insectivorous birds there either….