Barnacle geese are radically changing their migration patterns as a result of the warming climate.
Spring in the Arctic is starting earlier and earlier because of rising temperatures, and barnacle geese (Branta leucopsis) are speeding up their annual trip in a rush for breeding spots, with devastating consequences for newly hatched goose chicks.
In the spring, barnacle geese migrate 3,000 km from the North Sea to their breeding grounds in the Russian Arctic, stopping along the way for food and rest at sites along the Baltic Sea. But scientists now say that the geese are skipping these rest stops to reach the Arctic鈥檚 increasingly early spring, arriving at their destination up to almost two weeks ahead of schedule.
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This rapid, non-stop migration came as a surprise, says Bart Nolet at the Netherlands Institute of Ecology.
We used to think that geese would not be capable of making this journey without stopovers to refuel, he says.
The long way back
But an early arrival has its own problems: the geese are exhausted and need time to replenish their energies before laying eggs. They traditionally sync the hatching of their chicks with peak food quality, but the early arrival is causing a heightened struggle for food.
Under these conditions the baby goose chicks are finding it more difficult to become strong enough to survive the treacherous trip back.
The scientists say that the geese can avoid this problem not by simply speeding up their journey, but by setting off for the Arctic earlier 鈥� this would involve injecting some flexibility into their usually rigid departure times.
More than 5 per cent of the population have given up on migration altogether, preferring to breed in their wintering grounds, says Nolet. And this percentage is fast increasing.
But it鈥檚 risky, says Stuart Bearhop at the University of Exeter. It is thought that the geese make this trek because of the high-energy pay-off, and a loss of feathers after moulting around the breeding season renders them flightless and vulnerable to predators, he says.
But it might turn out that migration is no longer worth the hassle. 鈥淏y comparing migratory and non-migratory geese, we are currently studying the energetic costs and benefits of migration,鈥� says Nolet.
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