As the planet warms, animals that breed in the Arctic are at particular risk. But a new study reported in Current Biology March 1 offers some encouraging news: in an apparent response to pressures along their former migration route, a population of arctic geese has adapted quickly, establishing a new migration route and breeding site nearly 1,000km from their original range.
In addition, it appears that the new route has caught other geese and even birds of other species through cultural transmission (social learning). Therefore, the new population has already increased to up to 4,000 people.
“It is extremely exciting to see such a rapid evolution of new breeding sites and migration routes by a bird species that is considered very traditional in its behavior and site use,” said Jesper Madsen of Aarhus University in Denmark. “It offers some hope for ‘ecological rescue’ in times of very radical environmental change due to climate change and, more broadly, global change.”
“We are observing a new distinct bird population in real time,” he added. “This is very rare to see. The speed of development is amazing.”
Madsen’s team has been studying the pink goose population of Svalbard, Norway for more than 35 years. They have kept tabs on their population size and demographic variables, using a systematic program of marking and reviewing. About 20 years ago, they began receiving reports of geese appearing on migration in Sweden and Finland, which were confirmed as members of the Svalbard population.
To learn more, Madsen went to Oulu, Finland in the spring of 2018 and 2019 with his goose-catching team from Denmark as well as Dutch and Finnish partners. Their hope was to catch and tag some pink geese with GPS tags. They wanted to know where these geese were going and got an unexpected answer.
“It was a real surprise to see that half of the individuals marked in Oulu migrated northeast to Novaya Zemlya in northern Russia,” says Madsen. “From the tagging information, not only were we able to follow their new route, but we also got indications that females were breeding there. This location is about 1,000 kilometers east of the Svalbard breeding grounds.
“It was also nice to notice that the geese from the traditional corridor appeared on the new route and seemed to have changed. Therefore, social learning and tracking of individuals from the new route was an important phenomenon, which also explains how this evolution could you be so fast.”
With their new report, they have now documented a sharp formation of a new migration route and population for Arctic geese over the course of 10 to 15 years. The population has increased over time due to successful breeding and high survival rates combined with the continued migration of geese from the old to the new route.
Their ability to live on Novaya Zemlya has apparently been helped by warming in the region, they say. While the new population is not yet genetically or demographically isolated, they note that it already qualifies as a distinct population.
The new route has some drawbacks, says Madsen. For example, it is more. But they suspect the benefits of the new route and the reasons outweigh any downsides. The findings in geese show the importance of social learning in a changing planet, Madsen notes, especially in social animals, including birds, but perhaps also ungulates, wolves and whales.
“At a time when climate change and other human activities are threatening many species, especially arctic species, social learning may be a behavior that can offer advantages in avoiding some negative impacts, at least in the short term,” says Madsen.
Researchers say they hope to one day observe the geese in their new breeding grounds in Russia. For now, they will monitor the future growth of the new population using GPS tracking devices and remote sensing of the new environment.
This work was supported by the Danish Research Councils, the Danish Environment Agency, the Norwegian Environment Agency, Aarhus University and the Netherlands Polar Program of the Netherlands Research Council.