Stronger winds, driven by climate change, could affect seabird populations

Biologists in the UK say stronger winds projected my many climate change models could have a big impact on some coastal bird populations. When winds are strong, females take much longer to find food compared with their male counterparts.

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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 study suggests that climate change will exacerbate the differences and could ultimately affect population sizes.

To reach their findings, scientists with the Centre for Ecology & Hydrology at the University of Edinburgh and the British Antarctic Survey tracked shags — cormorant-like birds — on the Isle of May National Nature Reserve in south-east Scotland. Small tracking devices attached to the legs of birds helped 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.

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,” said Dr. Sue Lewis, of the University of Edinburgh’s School of Biological Sciences. “Forecasted increases in wind speeds could have a greater impact on females, with potential knock-on effects on the well-being of populations.”

The researchers said their findings may apply to other species of birds.

“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,” said Dr. Francis Daunt, of the Centre for Ecology & Hydrology. “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.”

Source: Summit County Voice

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