Large Heath

• Latin name: Coenonympha tullia
• Family group: Browns
• Countries: England, Scotland, Wales, Ireland
• Size: Small, Medium

Resident

Range declining.

The Large Heath is restricted to wet boggy habitats in northern Britain, Ireland, and a few isolated sites in Wales and central England.

The adults always sit with their wings closed and can fly even in quite dull weather provided the air temperature is higher than 14B:C. The size of the underwing spots varies across its range; a heavily spotted form (davus) is found in lowland England, a virtually spotless race (scotica) in northern Scotland, and a range of intermediate races elsewhere (referred to as polydama).

The butterfly has declined seriously in England and Wales, but is still widespread in parts of Ireland and Scotland.

Conservation status

• UK BAP status: Priority Species
• Butterfly Conservation priority: high
• European threat status: vulnerable
• Protected in Great Britain for sale only

European/world range

Occurs across Europe and Asia, and in Canada and western USA. It has declined seriously in many European countries.

Foodplants

The main foodplant is Hare's-tail Cottongrass (Eriophorum vaginatum) but larvae have been found occasionally on Common Cottongrass (E. angustifolium) and Jointed Rush (Juncus articulatus). Early literature references to White Beak-sedge, Rhyncospora alba, are probably erroneous.

Habitat

The butterflies breed in open, wet areas where the foodplant grows: lowland raised bogs, upland blanket bogs; and damp acidic moorland. Sites are usually below around 500m (600m in the far north) and have a base of Sphagnum moss, interspersed with dense tussocks of Hare's-tail Cottongrass and abundant Cross-leaved Heath, the main adult nectar source.

In Ireland, the butterfly can be found where manual peat extraction has lowered the surface of the bog, creating damp areas with local concentrations of foodplant.