As we tracked the remarkable flight of one small species of seabird into a typhoon

In 2018, 49,000 people in Japan were ordered to evacuate their homes as the strongest typhoon in 25 years, Typhoon Jebi, was on the landing course. Among those headed to the refuge was my colleague Ken Yoda, a professor of behavior and evolution, and his team, who were spending their annual field season studying a species of seabird called the striped petrel.

Typhoon Jebi broke wind records at 100 Japanese weather stations with sustained winds of 120 mph. These winds did damage almost 98 thousand housescaused insurance claims of US$13 billion to US$14 billion (£11.4 billion to £12.3 billion) and resulted in the deaths of seven people.

Typhoon Jebby’s experience made Ken realize that he had amassed a unique set of tracking data that could be used to study how these seabirds respond to storms in the open ocean. This information revealed the petrels that he sometimes studied did the unthinkable: flies straight to the eye a thunderstorm.

So how does an animal that weighs as much as a pint of milk survive these conditions?

Using GPS tracking data collected by tagging banded petrels over 11 years on Awashima Island in the Sea of ​​Japan, Ken Yoda teamed up with biologists Manas Lempidakis and myself and meteorologist Andrew Ross to find out. Manos analyzed the tag data to find out which birds fly over the Sea of ​​Japan during the passage of a typhoon or tropical storm. He then analyzed their GPS tracks relation to the wind.

We never thought the result would show that petrels sometimes fly right into the eye of the storm. Several previous studies tracking seabird responses to storms have shown that adults fly hundreds of miles to bypass them. However, our results showed that petrels pursued the storm, tracking it for eight hours.

How it works

Like albatrosses and other trumpet-nosed birds petrels, so called because of the location of their nostrils, are adapted to windy conditions, using wind energy to fly with a slight swing.

Theirs wing shape allows them glide long distances without much loss of height. Pipers tend to live in windy areas, including many of these prone to cyclones.

If petrels fly to the eye of the storm, sometimes they are in or near the eye wall (the area around the eye of the storm where the strongest typhoon there are winds). But there comes a point when they cannot match the speed of the wind. When this happens, the birds begin to drift with the wind and lose control of their direction of travel.

We used statistical modeling to delve deeper into petrel movement. This work showed that petrels sometimes avoided storms, but only when they were far out to sea and had a clear path around the storm system.

Most of the petrels in the studied colony foraged near the Japanese mainland. It was here that, when trapped between the storm and the ground, the birds flew to the eye of the storm.

1/6 New paper! A banded petrel shows a strange response to typhoons by flying towards the eye of the storm (bird tracks in color, eye of storm in black). The work is the same @ELCShepard @AndrewRossLeeds & Ken Yoda @PNASNews #ornithology #sea bird @BES_Move_SIGhttps://t.co/J6R0iNv0yV pic.twitter.com/BLg6siDu7i

— Emmanuel (Manos) Lempidakis (@Manos69188358) October 4, 2022

In the village northern hemisphere, cyclones move counterclockwise. Therefore, birds foraging near Japan may have been caught by strong onshore winds behind the storm’s eye and forced to fly over land.

Flying above the ground is dangerous for petrels due to the risk of uncontrolled landings. These birds, so agile in the air, are unwieldy on land. They struggle to take off even under normal conditions, making them vulnerable to predators, including crows and birds of prey.

A safer option is to fly towards the eye of the storm, away from the ground. But birds need to know where land is to avoid it. While adults seem to have an internal map, studies show that young birds have not had time to accumulate this knowledge. This may help explain why young boletus which are sometimes washed away by the thousands after storms.

Bad weather ahead

We know very little about how seabirds respond to storms because such extreme weather is, by definition, a rare occurrence. And no two storms are alike. So we need massive amounts of tracking data (and luck) to capture the moments when birds are exposed to storms and find patterns in their behavior.

One of the things that makes our research particularly valuable is the amount of data we had. We studied the data of 401 petrels over 11 years. Within this, 75 birds flew during ten typhoons or tropical storms, making this the largest data set of animal tracking during a storm at the time of publication.

But the strategy of flying by eye is probably only a variant of fast flight, the wind– adapted birds for example, albatrosses and petrels. We need more data to understand whether seabirds with different flight styles and energy costs respond to typhoons. increasing intensityand potentially in size and duration.

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