Researchers at the Max Planck Institute of Animal Behavior in Germany and Swansea University have revealed how different seabird species use distinct strategies to cope with cyclones, with some flying directly into the storm, and others using avoidance tactics.
A significant amount of research has focused on how animals may be affected by extreme heat, but less is known about how animals respond to extreme winds. Elham Nourani, a Postdoctoral Researcher at the Max Planck Institute of Animal Behavior and first author of the study, was keen to understand how seabird species respond to cyclone-strength winds and whether certain wind speeds are avoided or preferred by birds.
With the help of 300,000 hours of flight data from 18 different species, Elham and researchers at Swansea University investigated how the flight characteristics varied among different species.
The findings, published in Current Biology, showed that birds living in windier environments, such as albatrosses, are faster fliers. This makes sense, because all birds have to fly faster than the wind in order to determine their own direction, and not simply be drifted where the wind blows. Albatrosses therefore fly faster than tropical species such as the red-tailed tropicbird that experience relatively low wind speeds on a daily basis.
Professor Emily Shepard of Swansea University explained: “The situation becomes more complicated when we start to consider what happens in storms because the strongest wind speeds occur over the tropics, not the Southern Ocean. So, while albatrosses can fly in almost all conditions they experience, tropical species must have strategies to cope with cyclones, when winds may be twice what they are able to fly in”. This adds to other evidence that tropical seabirds are likely to show long-range avoidance of extreme events.”
To their surprise, the researchers also unearthed a handful of examples of wind avoidance in albatrosses. This was particularly unexpected as the albatrosses avoided wind speeds that they were able to fly in in other scenarios.
One such case was seen in an Atlantic yellow-nosed albatross tracked in this study, which encountered a storm off the coast of Uruguay in November 2014. The bird avoided 68 km/h winds by flying into the eye of the storm where wind speed was much lower, around 30 km/h. It flew within the eye for12 hours before leaving the eye after the storm had moved away from the coast.
"We know that wind-adapted birds like albatrosses fly in very strong winds. What surprised me the most was that even these species avoid strong winds from time to time, and that they can do so by flying into the eye of the storm," Elham explained.
The researchers suggest this may be a strategy they use to avoid being drifted somewhere they do not want to go.
Elham concluded: “As a result of the climate crisis, storms will become more frequent and stronger. So, the question is how seabirds will be impacted by this. Understanding the wind speeds that different species can operate in is a key part of this. What seems like an extreme wind to a tropical species is what an albatross encounters on a near-daily basis, so our definition of extremes needs to vary depending on the species we are talking about.”
Read the original paper 'Seabird morphology determines operational wind speeds, tolerable maxima, and responses to extremes' in Current Biology.