Nagasaki: Invasive Squirrels Rampant on Island

The Yomiuri Shimbun
A member of the capturing team caught a Pallas’s squirrel using a trap in Iki, Nagasaki Prefecture, on Nov. 26.

IKI, Nagasaki — A special team has been formed to capture Pallas’s squirrels on Iki Island, Nagasaki Prefecture, as there has been no end to the amount of damage caused by the invasive alien animals, which includes chewing on communication cables.

The critters, also known as Taiwan squirrels, continue to increase in number on the island, and the Iki city government has been working to exterminate them. Although the number of captured squirrels is increasing each year, the municipality cannot keep up with the speed of their reproduction.

Thanks to the efforts of the special capturing team and other factors, the number of animals caught in fiscal 2020 reached 30,813 as of the end of November, about 7,000 more than the total number in fiscal 2019. The city government hopes that the trend will rise further.

The team was formed in May by five members who were hired to accelerate the capture of the squirrels. They are among hunting club members and others, who have hunting licenses and are familiar with handling animals.

The members set traps in city-owned forests and around private houses and patrol the area five days a week to catch the tree-dwelling rodents.

Pallas’s squirrels mainly live in Southeast Asia and are about 40 centimeters long. They also give birth three times a year or so, depending on their environment. The squirrels were brought to zoos across Japan since the early Showa period (1926-1989), then they escaped from the zoos, multiplied, and have become wild in many places.

According to the city government and others, the number of squirrels on the island has rapidly increased because there is an abundance of nuts available for them to eat and a lack of natural enemies such as raptors. In fiscal 2019, a record 23,956 animals were captured, 6.7 times more than 10 years ago.

The city government has been trying its best to catch them by encouraging citizens to install traps, but the number of cases of TV and telephone cables being bitten has been increasing each year, and last fiscal year, a record 94 cases were confirmed. The number of cases has quadrupled in the six years since fiscal 2014. Fruit trees and vegetables have also been damaged.

In 2019, a problem occurred where some broadcasters’ programs could not be seen throughout the island. The cost of countermeasures, such as cutting down trees in the vicinity to keep the squirrels away from the cables, will amount to about ¥40 million over the five years to fiscal 2019.

“The speed of reproduction is so fast that it is impossible to simply ask citizens for their cooperation in capturing them. We hope that the capturing team will be able to control the damage as much as possible,” the city government said.

There is a possibility that damage to the communication cables may prevent the broadcasting of disaster prevention messages. Since October 2020, the city has raised the reward for citizens who catch a squirrel from ¥700 to ¥800.

“From now on, we would like to analyze the data of the places where squirrels are caught, so that we can catch them more efficiently,” a city official said.

The Yomiuri Shimbun
A cable apparently damaged by Pallas’s squirrels