Small Dark Yellow Underwing

The Small Dark Yellow Underwing (Coranarta cordigera) is a rare, day-flying Scottish Highland moth (24–28mm wingspan) known for its distinctive dark, white-marked forewings and yellow-orange underwings, which it displays to startle predators. It is a priority conservation species that feeds exclusively on Bearberry, appearing in high-altitude moorlands between April and June. 

Interesting Facts About the Small Dark Yellow Underwing:

• Rare Highland Specialist: This moth is found only in specific high-altitude moorlands (200-650m) in the Scottish Highlands, particularly in the Cairngorms, Aberdeenshire, Angus, and Highland Perthshire.

• Unique Food Source: The caterpillars feed exclusively on Bearberry (Arctostaphylos uva-ursi).

• Diurnal Behavior: Unlike many moths, it is most active and flies during sunny days, often seen nectaring on heather and other moorland flowers.

• Disguise and Panic: When resting on rocks or lichen-covered posts, its mottled dark forewings provide excellent camouflage. When threatened, it reveals the bright yellow-orange underwings to surprise predators before quickly escaping.

• Identification: It is often confused with the more common Beautiful Yellow Underwing (Anarta myrtilli), but the Small Dark Yellow Underwing has distinct white markings on its dark grey/brown upper wings.

• Conservation Priority: Listed as a priority species on the UK Biodiversity Action Plan and in Scotland.

• Potential New Discovery: A 2022 discovery showed the species potentially moving away from its usual habitat and food plant, raising hopes that it might be adapting to feed on Bog Bilberry, potentially meaning it is present in more locations than previously thought.