Stronger winds could affect seabirds

Stronger winds forecast as a result of climate change could impact on populations of seabirds, a University study suggests.

Research into a common UK coastal seabird 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.

Adverse weather

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.

Foraging time

Researchers from the University, the Centre for Ecology & Hydrology (CEH) and British Antarctic Survey carried out their two-year study into cormorant-like birds, known as 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.

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.

Long-term study

Scientists say their findings may apply to many other species in which there are sex differences in foraging.

Their research, carried out as part of a long-term CEH study on the island that began in the 1970s, was funded by the Natural Environment Research Council and published in the Journal of Animal Ecology.

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 well-being of populations.

Dr Sue LewisSchool of Biological Sciences, University of Edinburgh