Fox that crossed the ice threatens reintroduced dormice on Estonian island
A colony of garden dormice reintroduced this summer to Estonia's Suur-Pakri Island now shares its predator-free habitat with a fox that crossed over during a harsh winter. Ecologists are watching to see whether the animals survive until spring.
A small colony of garden dormice (Eliomys quercinus) released this summer on Suur-Pakri Island, off the Estonian coast, has run into an unexpected complication: a fox has made its way onto what was supposed to be a predator-free island.
The garden dormouse is a native Estonian species that went extinct due to human activity, though the exact cause remains unknown. The last wild sighting in Estonia was in 1986, and the species disappeared from neighboring countries around the same time. This summer marked the first reintroduction of a small colony since then.
Encouraging early signs
Of the 20 animals released, more than half were confirmed alive when researchers last visited the island a couple of weeks ago. Ecologist Marko Mägi called this a surprisingly good result for a small, zoo-raised animal, and said there is cautious optimism some individuals could survive until spring. However, because the dormouse is small, short-lived and hibernates through winter, it remains unclear whether any will still be alive when spring arrives.
An unplanned predator
Suur-Pakri was originally chosen for the reintroduction precisely because it had no predators. Surveys conducted last autumn confirmed the island was safe. But a harsh winter froze the surrounding sea, allowing a fox to cross the ice onto the island. This summer, trail cameras and a direct sighting confirmed the fox is now resident there.
Mägi noted that garden dormice are nocturnal and readily climb trees, where foxes cannot follow, though their paths may still cross. Fortunately for the dormice, the island hosts plenty of other small rodents that are of greater interest to the fox — making the garden dormouse, in Mägi's words, more of a gourmet treat than a staple prey item. Researchers now plan to monitor whether the dormice colony can persist alongside its new neighbor.
