Arctic animals are migrating earlier in the year due to climate change

Animals in the Arctic, including reindeer and golden eagles, are migrating earlier due to climate change, say researchers who have gathered a huge amount of data to study the behaviour of 86 Arctic species over the past three decades.

“We have the ability to monitor animal movements on a very large scale,” says Eliezer Gurarie at the University of Maryland. “It seems that animals are unknowingly responding and adapting to climatic changes, and have been doing for years.”

Gurarie and his team used GPS tags and satellites to track the spring migration of more than 900 female reindeer over the past 15 years. They discovered that the females are migrating to give birth approximately a day earlier year on year, probably as a result of warming temperatures.

“These patterns are tracking global warming,” he says. The Arctic is experiencing some of the worst-known effects of climate change, warming twice as fast as the global average.

Earlier birthing times can be risky in northern parts of the Arctic, says team member Gil Bohrer at Ohio State University. “There are higher chances of these offspring encountering strong freak storms,” he says. If they do, many will inevitably die because they cannot handle extreme conditions that can see up to half a metre of snow.

Reindeer are already in decline, says Gurarie, and climate change is worsening the situation. This poses a threat to people living in the region who rely on them for fur and meat.

Similarly, golden eagles – which usually nest in the Arctic tundra – have been starting their spring migration half a day earlier each year over the past 25 years.

“The day-to-day variation of climate change is very small,” says Bohrer. “To understand how animals respond to climate change, you need a very long period of observation – something that has only recently been possible.”

The researchers’ archive of Arctic animal movement currently contains more than 15 million data points related to 8000 animals. “Our archive can help to advise management techniques to preserve endangered species, as climate change only becomes more extreme,” says Bohrer.

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