Barnacle geese are choosing new feeding sites to cope with climate change, according to Scottish researchers.
A team from St Andrews University, along with Norwegian, Dutch and British colleagues, found that the birds were flying further north in the Arctic.
The study is one of the first to provide hard evidence that wild animals are inventing new ways to cope with changing habitats.
The findings are based on 45 years of observations by experts.
The teams found that the migratory birds, which traditionally fuelled up, or staged, just South of the Arctic circle in Norway now mainly staged in northern Norway far above the Arctic circle.
Shifting patterns 'make sense'
Individual geese changed to a new route with other geese learning the new habit from each other, according to the findings.
The researchers added that barnacle geese had shifted their migratory route on their journey from the UK to their breeding grounds on Svalbard, a Norwegian archipelago, within the last 25 years.
Dr Thomas Oudman of the school of biology at St Andrews, said: "It makes sense that the birds went even further north, because where snow used to be very common there at the time of their arrival in Norway, these days it is often freshly green there: the most nutritious stage.
"What surprised us is that it is mainly the young geese who have shifted. The youngsters are responding to a trend they could not have experienced during their short life."
Adult geese are also increasingly shifting north, although they often return to the traditional areas in their old age.
Dr Oudman added: "These patterns point at a complex social system, which enables the geese to rapidly colonise newly available areas."
Contrary to most other migratory birds, barnacle geese flourish even while their natural habitat is rapidly changing.
Barnacle geese are able to adapt to climate change due to the availability of alternative places with sufficient food at the right time, and without the threat of disturbance from humans or other dangerous animals.
The availability of alternative habitats may also help other animals to adapt to climate change.
Animal species which are less sociable or explore less may take much longer to discover such places.
The conclusions are based on analysis of 45 years of observations by the Norwegian Institute for Nature Research, St Andrews University, the University of Groningen in the Netherlands, BirdLife Norway and the British Waterfowl and Wetlands Trust.
The research has been published in the journal Global Change Biology.