One of the biggest wildlife spectacles of autumn happened last month. Huge flocks of beautiful black and white barnacle geese migrated from their Arctic summer home in Spitsbergen, far to the north of Norway, to their winter lands on the Solway Firth, Scotland. About 30,000 birds flew down, taking advantage of good northerly winds.

But the numbers of geese arriving from the Arctic have come under pressure from an unexpected threat. Polar bears have been stealing the eggs and goslings of the barnacle geese from their nests on the ground in Spitsbergen. Usually the polar bears hunt seals offshore among the pack ice and leave the geese alone. But the Arctic sea ice has dwindled and many bears could not reach their hunting grounds and were stranded onshore. Without seals to hunt, the hungry bears turned to picking off the eggs and goslings. “Although a single clutch of eggs is not much food for a hungry polar bear, vast numbers can be hoovered up in a single short visit by the bears,” explained Dr Larry Griffin at the Wildfowl & Wetlands Trust at Caerlaverock, Solway.

As a result, thousands of goslings have been lost and the numbers of birds migrating to Solway were hit hard, although numbers were made up to some extent by geese nesting in cliffs in Spitsbergen, out of reach of the polar bears. But if the change in polar bear hunting continues in future years, the ground-nesting barnacle geese of Spitsbergen could face a bleak future.