Predicting when seabirds soar

A team of scientists, led by ZSL (Zoological Society of London), have shown for the first time that wind speed can be used to predict flying behaviour of seabirds, which may help in understanding how future changing wind patterns may affect the behaviour of these birds.

Manx Shearwaters at sea
The Manx shearwater is currently Amber Listed as a bird of conservation concern in the UK

The study examines the impact of localised wind conditions on seabird behaviour and used a new style of tracking device to record flying data of a common ocean-flying seabird, the Manx shearwater (Puffinus puffinus), in more detail than ever before.

By monitoring shearwater burrows on Lundy Island in the Bristol Channel, the team were able to capture birds as they left them and affix a small, temporary GPS tracking device to their backs, which recorded data about the bird’s location 10 times per second.

When matched up to satellite-measured wind condition data, the team found that wind speed and direction could be used to predict whether the individuals were engaging in a ‘flap-like’ or ‘soar-like’ flight.

Importantly, they found that soaring was significantly more likely to occur in crosswinds and tailwinds faster than eight metres per second. These periods of wind-powered soaring require less energy than flapping, and are used by many seabirds to reduce the energy costs of migration or foraging trips to sea.

This suggests that the specific conditions that enable soaring are beneficial to the birds, as they may allow them to reduce energy expenditure.

The results outline a clear way in which changing wind conditions could shape the foraging and migratory behaviour of open-ocean seabirds, as species may alter their behaviour to encounter conditions favourable to soaring.  Understanding how environmental conditions like wind impact behaviour is an important topic not just for better understanding the lives of these animals, but also to understand how our changing environment may impact their future.

The flight behaviours of the Manx shearwater, which is currently Amber Listed as a bird of conservation concern in the UK, are seen in many other more vulnerable seabird species, such as  albatrosses, many of which are Critically Endangered on the IUCN Red List.

Lead author Rory Gibb, from ZSL’s Institute of Zoology, said: “This is the first time that these type of tracking devices have been used to look at exactly what these birds are doing second by second at such high resolution, rather than just recording their overall location, and we were quite surprised by our findings.

“While we knew that wind conditions were clearly important for soaring behaviour, we weren’t expecting such a clear shift from flapping flight to soaring at a specific wind speed.

“This suggests we might be able to use this threshold to investigate the importance of wind for key behaviour such as migration. As climate change threatens to continue to disrupt weather patterns worldwide, including wind, it’s vital that we understand how this will affect the behaviour and movement of different species, so we can best work to ensure their survival.”

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