Rare Siberian flying squirrels spotted along Ulsan's Taehwa River

Two Siberian flying squirrels, a natural monument and class II endangered wildlife species, have been spotted near a walking trail in Ulsan, adding to the list of rare wildlife that has been seen in the city.

Two Siberian flying squirrels were confirmed to be inhabiting an area along a riverside walking trail in the middle reaches of the Taehwa River in Ulsan, the city government said Sunday.

The squirrels were first spotted on Sept. 9, when nature guide Lee Chan-sook discovered one inside a tree hollow made by a woodpecker and photographed it while walking along the trail. Yoon Gi-deuk, a photographer and scientist, later visited the site on Sept. 17 and 23 and captured video footage of two flying squirrels entering and leaving the hollow.

Siberian flying squirrels measure about 15 to 20 centimeters (5.9 to 7.9 inches) in body length and are known to glide between trees using winglike membranes of skin stretched between their front and hind legs. They are nocturnal animals that primarily inhabit forests, making sightings relatively rare.

Flying squirrels have previously been confirmed in forested areas of Ulsan, including nearby Seoknam Temple, Baenae Village and the cypress forest on Mount Cheonma. However, this is the first time a nest has been discovered along an area regularly used by residents.

The discovery has also raised interest in whether the two squirrels could be a breeding pair.

“Male and female flying squirrels normally live independently, so the fact that the two were seen together suggests they may be a male and a female,” Han Sang-hoon, a researcher at the Korean Peninsula Wildlife Research Institute, said after reviewing the footage. “They appear to be preparing to breed, but they are not believed to have produced offspring yet, so further monitoring is needed.”

While the squirrels are inhabiting near Taehwa River, the Ulsan city government has decided not to disclose their exact habitat location to protect them.

The discovery is the latest in a series of sightings of rare wildlife in Ulsan.

In June, three Reeves' turtles, a native freshwater species designated as a natural monument and a Class II endangered wildlife species, were found in the Motsan wetland along the Hoeya river in the city's Ulju County.

In January, several rare bird species including golden eagles and black storks were observed around Hoeya dam and the Hoeya wetland in Ulju County. Both birds are designated as Class I endangered wildlife species.

The repeated sightings of species with different habitat requirements suggest that Ulsan's forests, rivers and wetlands are functioning as habitats capable of supporting a diverse range of wildlife.

Flying squirrels depend on forests with connected tree canopies, while Reeves' turtles primarily inhabit rivers and wetlands. Birds including golden eagles and black storks also require suitable habitats where they can feed and rest.

While rare wildlife is now increasingly being spotted across Ulsan, the city was once dubbed a smokestack city. Home to factories operated by some of Korea's largest companies, Ulsan became synonymous with pollution and environmental degradation during its rapid industrialization. The Taehwa River was once so severely polluted and plagued by foul odors that it earned the nickname River of Death.

The transformation began in earnest in 2004, when Ulsan declared its ambition to become an ecological city. Continued efforts to improve water quality and restore wetlands gradually revived the ecological functions of urban areas centered on the Taehwa River.

“The discovery of Siberian flying squirrels, a designated natural monument species, along the Taehwa River walking trail is welcome news that highlights the river’s ecological value,” an Ulsan city official said.

BY KIM YOUN-HO [[email protected]]