An entire colony of endangered narrow-headed ants, potentially containing as many as 5,000 insects, was stolen from Chudleigh Knighton Heath nature reserve in south Devon, England. Devon Wildlife Trust reported the theft after researchers discovered that a known nest had been dug out during routine checks in mid-October.

The surrounding ground showed clear signs of digging with a spade, and investigators found a hollow where the nest had previously been. The exact number of ants taken is unknown, but a single mature nest can contain between 1,000 and 5,000 ants, including one or more breeding queens that can live for up to 25 years.

Chudleigh Knighton Heath is the last remaining stronghold for narrow-headed ants in England. Small populations also survive at a handful of sites in Scotland. The reserve's most recent survey recorded 142 active nests, making the loss of even one established colony a significant setback for conservation work.

The species has declined over the past century as its preferred heathland habitat has disappeared through development and agricultural changes. Conservationists warn that colonies develop slowly and that mature nests represent years of growth that cannot quickly be replaced.

The reserve is designated a Site of Special Scientific Interest, and narrow-headed ants are classified as nationally rare and near threatened on the International Union for Conservation of Nature's Red List. Deliberately damaging or disturbing the protected site, including removing material, is a criminal offense.

Devon Wildlife Trust has reported the theft to Devon and Cornwall Police, who are asking anyone with information to come forward. The trust is also reviewing security at the reserve and continuing regular monitoring by staff and volunteers.