Stronger winds forecast as a result of climate change could impact on populations of seabirds, a new study suggests.
Research into a common UK coastal seabird, the European shag, showed that when winds are strong, females take much longer to find food compared with their male counterparts. Researchers expect that if wind conditions worsen - as they are forecast to do - this could impact on the wellbeing of female birds, and ultimately affect population sizes.
Scientists from the University of Edinburgh, the Centre for Ecology & Hydrology (CEH) and the British Antarctic Survey carried out a two-year study into the cormorant-like Shags on the Isle of May National Nature Reserve in south-east Scotland. Small tracking devices were attached to the legs of birds and measured how long they foraged for fish in the sea.
Researchers expect that if wind conditions worsen, as they are forecast to do, this could impact on the wellbeing of female birds and ultimately affect population sizes
In many seabird species, females are smaller and lighter than males, and so must work harder to dive through turbulent water. They may not hold their breath for as long, fly so efficiently nor dive as deeply as males. The latest results suggest that in poor weather conditions, this sex difference is exaggerated.
The scientists found that when coastal winds were strong or blowing towards the shore, females took much longer to find food compared with males. The difference in time spent foraging became more marked between the sexes when conditions worsened, suggesting that female birds are more likely to continue foraging even in the poorest conditions.
A brisk westerly wind creating rough conditions along the west cliffs of the Isle of May. European shags loiter around nest sites (Photo: Mark Newell).
The research was carried out as part of the long-term CEH seabird study on the Isle of May that began in the 1970s.
Lead author Dr Sue Lewis from the University of Edinburgh said, “In our study, females had to work harder than males to find food, and difficult conditions exacerbated this difference. Forecasted increases in wind speeds could have a greater impact on females, with potential knock-on effects on the wellbeing of populations.”
Co-author Dr Francis Daunt, of the Centre for Ecology & Hydrology, said, “Most of the research on climate change has focused on the effects of warming, but there is growing concern about increasing wind speeds and frequency of storms. This study shows one way in which wind could affect wild populations, and may be widespread since many species have sex differences in body size.”
The research was funded by the Natural Environment Research Council and published in the Journal of Animal Ecology.
The full paper is open access at the Journal of Animal Ecology: Contrasting responses of male and female foraging effort to year-round wind conditions, doi: 10.1111/1365-2656.12419
The University of Edinburgh issued a press release for this story.
The study was carried out as part of CEH's long-term Isle of May monitoring project