Die Hard: UK mulls contraception for gray squirrels

They have been the scourge of trees and the local red squirrel in Britain since their introduction from the United States in the 1870s.

But government scientists are now planning drastic measures to reduce gray squirrel populations by adding oral contraceptives to their food.

Before going that far, the Animal and Plant Health Agency (APHA) tested special feeding boxes in the forests of northern England and Wales.

About 70 percent of the gray squirrel population used crates that have weighted gates to keep most other animals out.

Department of Environment, Food and Rural Affairs Chief Scientific Adviser Gideon Henderson said the trials have great potential for non-lethal management of gray squirrel populations.

“This will help red squirrels return to their natural habitat, while also protecting the UK’s forests and increasing biodiversity,” he added.

Vanessa Fawcett of the Red Squirrel Survival Trust said research into the development of oral contraceptives for animals has progressed.

“Without effective conservation management, red squirrels could face further extinction across the UK.”

Contraceptives have not yet been used in trials, but APHA researchers said they would be effective for both men and women.

There are currently 2.7 million in Britain and their number is increasing from 140,000 small red squirrels.

The Grays compete with the Reds for food and are also carriers of the smallpox virus squirrels. They are immune, while the Reds are not, and infection is almost always fatal.

The high density of gray squirrels also threatens the health and survival of young trees as they strip off the bark, weakening and killing them.

The traditional shooting of the animals has proven to be ineffective, as they multiply rapidly and their numbers can quickly recover.