How frigatebirds can fly nonstop for weeks on end

July 2, 2016, 6:04 p.m.
Two frigatebirds in the sky
Photo: Ecuadorpostales/Shutterstock

The flight prowess of these "jet fighters of the sky" is well known. Frigatebirds are famous — or infamous — for harassing other birds in the air until they spit up their fishy catch, then the aggravating frigatebird will dive to catch the stolen meal.

But more than just being incredibly fast, agile flyers, they're also able to stay aloft for weeks on end.

Frigatebirds don't have waterproof feathers like most seabirds, so they can't land in the water, hence being such a menace as one strategy for getting a meal. As long as they're over the ocean, they have to stay on the wing, and that can sometimes mean staying in flight for as long as two months at a stretch. How do they do it?

New research by ornithologist Henri Weimerskirch sheds some light on this incredible strategy. They can fly to unbelievable heights, surpassing 12,000 feet above sea level, and are the only known bird to purposefully fly into a cloud. But it's all part of the plan.

NPR reports:

Over the ocean, these [cumulus] clouds tend to form in places where warm air rises from the sea surface. The birds hitch a ride on the updraft, all the way up to the top of the cloud...One of the tagged birds soared 40 miles without a wing-flap. Several covered more than 300 miles a day on average, and flew continuously for weeks. They are blessed with an unusual body. No bird has a higher ratio of wing surface area compared with body weight — something called "wing loading."

Writing in the journal Science, the researchers discovered that frigatebirds have also capitalized on a lucky coincidence. Winds that form these updrafts in the atmosphere also disrupt waves at the sea surface...And when the regularity of waves is disrupted, deeper water rises to the surface, carrying with it things such as phytoplankton that attract small fish. The small fish attract bigger fish, which creates the feeding frenzy that frigatebirds need to dine.

So these savvy frigatebirds are able to dive down to partake in a feeding frenzy, then use the same updraft that helped cause the feeding frenzy to hitch a ride back up into the heights of the sky, staying aloft with little energy until the dinner bell rings again. They are jet fighters and marathoners in one.