Common swifts, the world’s fastest migrating bird, are even faster than scientists thought
Under ideal conditions, common swifts can travel over 500 miles per day for over a week, report the scientists. It seems like an unimaginable feat for such a small bird, but the Swifts have adopted a clever strategy that makes these epic migrations possible.
As a migratory bird, common swifts (Apus apus) are aptly named. These highly mobile creatures spend over 80% of their life in the air when not in breeding mode, and much of that time is spent migrating from northern Scandinavia to their wintering destinations in Africa. western and central.
For these long-distance migrations, scientists had previously estimated the average speeds of 310 miles per day (500 km / day), but new research published in iScience updated this figure to 570 km / day. More impressive – not that that’s not impressive enough – new study shows swifts can travel farther and faster than previously thought. At their fastest speed, swifts can travel over 830 km per day for nine hours.stretch of the day. The new article was written by Susanne Akesson and Giuseppe Bianco of the Center for Animal Movement at Lund University in Sweden.
The researchers used miniature geolocators to track 45 adult rock swifts on migrations in 2010, 2012 and 2014 (the devices weighed less than 3% of the birds’ body mass, so as not to slow them down). Of these, 24 were later captured again; swifts almost always return to their specific breeding sites, allowing their trackers to recover after a single season of migration. Akesson and Bianco managed to recover 20 swifts that recorded their movements for a full year, including fall and spring migrations.
As the data show, “Common Swifts breeding in the northernmost part of European range” covered, on average, about 6,150 miles (9,900 km) during fall migration and about 4,900. miles (7,900 km) in the spring, “exceeding those recorded. for populations in southern and central Sweden ”, according to the study.
Swifts use a combined strategy to achieve these record trips, “including a high stopover refueling rate, flights and forages during migration, and selective use of tail winds,” the scientists write. By eating small meals along the way, swifts are able to reduce the “high energy cost of flight,” according to the study.
As noted, birds also benefit from the winds. Somehow, they know when the winds will be most favorable. Scientists are not entirely sure how they are able to do this, but they suspect it is a reaction to the change in air pressure caused by passing weather systems. Either way, the winds give swifts a 20% increase in spring compared to fall. The winds are the greatest help when crossing the Sahara and the Mediterranean Sea. Interestingly, the winds may explain why the previous speed estimates for the swifts were too low.
Swifts may be the fastest migrators, but other birds are equally impressive for long-distance travelers. Last year, scientists reported on a record-breaking flight by a barge with a barge (Limosa lapponica). This bird flew nonstop for 11 days, covering 7,987 miles (12,854 km) of From Alaska to New Zealand. Scientists suspect that bar-tailed godwits have a special metabolism that makes this possible, as well as an ability to go without sleep for an extended period of time.
After: Record-breaking bird just flew nonstop from Alaska to New Zealand.