Swifts Can Fly More Than 500 Miles in a Day

One of the most interesting things about swifts is that they get together in late spring and summer for what is known as “screaming parties.” Sometimes dozens of birds will gather and careen through the air in tight formations, all the while shrieking as they dive and soar and avoid hitting chimneys and trees. This cacophonous, frenetic behavior typically happens during the breeding season.

But when they aren’t breeding, swifts stay in the air for up to 10 months without stopping. And they’re known for their speed. That’s how they got their name, after all. 

Now, researchers in Sweden have found the speedy common swift travels even faster and farther than previously thought.

“Their airspeed (10 meters/second) on migration is similar to many other birds, but they have display flights at nest sites, where they will reach 110 kilometers/hour [68 miles/hour] in steady flapping flight, which is the highest speed for such flights for any bird,” study co-author Susanne Åkesson of Lund University in Sweden, tells Treehugger.

During migration, they fly faster than 500 kilometers (310 miles) per day, which is the fastest predicted speed for any migratory bird, Åkesson says. Most other migratory birds travel between 100-300 kilometers (62-186 miles) per day.

For their study, Åkesson and her team attached small geolocation devices to 20 adult breeding common swifts. They started tracking them when they departed Swedish Lapland, one of the most northern breeding locations for the birds in Europe.

The birds left the area in early August through early September. They arrived in their wintering location south of the Sahara in North Africa about six weeks later.

The researchers were able to recover many of the devices after one migration season. The data supported their expectation that the swifts would race to very high migration speeds. But they were surprised how fast the birds actually traveled.

Faster and Farther

According to their tracking data, common swifts traveled 570 kilometers (more than 350 miles) on an average day. But they found that they are able to go significantly farther and faster. In the study, swifts were recorded going more than 830 kilometers (more than 500 miles) per day over nine days.

Swifts are able to be so, well, swift, on these migratory flights because of several strategies, Åkesson explains.

“Those high speeds are possible for the swifts to reach thanks to their small size, their high fuelling rate, their possibility to forage a little every day on aerial insects (they do not have to carry so large fuel reserves during their migrations and can therefore save energy),” she says.

“They have as we say a fly-and-forage strategy on migration. In addition, they can predict good wind conditions for their migratory flights and time their departures to make the best out of the wind situation. This will give them extra support when crossing barriers such as the Sahara desert and the Mediterranean Sea on spring migration.”

Although it’s nice to have bragging rights in a fastest birds competition, the researchers believe their findings are key for much more critical reasons.

“It is important to learn how birds have adapted to cope with long migrations and how they are able to use weather and winds on migration as such patterns may change for different regions due to climate change,” Åkesson says.

“Swifts furthermore feed on insects which had been declining in many regions, and because of this may be deprived from having access to food, and the declining insect may therefore affect the possibility for swifts to sustain migrations and to survive during breeding and wintering.”