Danish killer slugs disappear after dry spell

Killer slugs, a persistent garden pest in Denmark, have all but vanished from backyards this season, leaving even slug-hunting ducks without their usual prey, DR reports.

Ingrid Boldsen, a resident of Kolind on the Djursland peninsula, typically relies on her Indian runner ducks, Anni and Anders, to keep the invasive Iberian slug—known locally as the “killer slug”—in check. But recent searches of her wooded property have turned up almost none.

“There aren’t many right now,” Boldsen said. “Sometimes Anni finds a clutch of eggs and gobbles them up, but that’s about it.”

The scarcity follows weeks of unusually dry weather, according to Stine Slotsbo, a senior researcher at Aarhus University’s Department of Ecoscience and a specialist in the species.

“They’re hiding,” Slotsbo explained. “They’ve likely found moist refuge underground.” She cautioned that it remains unclear whether recent rainfall will coax them back above ground, as their reappearance depends on soil saturation levels.

For now, Boldsen’s ducks are making do with earthworms and whatever else they can scavenge. “It’s like the rest of us,” she said. “When there’s no caviar or shrimp, you eat oatmeal.”

The Iberian slug, classified as an unwanted invasive species by the Danish Environmental Protection Agency, is known for devastating vegetable gardens. Official guidelines recommend rapid euthanasia—by boiling water or garden shears—to minimize suffering.