Large Heath

The Large Heath (Coenonympha tullia) is a specialist butterfly, with Scotland acting as a crucial stronghold for the species due to its extensive peatlands. Found from mid-June to mid-August, these butterflies are highly sedentary bog-dwellers that almost always rest with closed wings, revealing spots adapted to confuse predators. 

Here are some interesting facts about the Large Heath in Scotland:

• Spotless "Scottish" Variant: While large heaths in England have large, obvious underwing spots, the subspecies found in Northern Scotland (scotica) is almost entirely spotless.

• Specialist "Bog Buddy": They are strictly found in wet, acidic boggy areas like upland blanket bogs and lowland raised bogs.

• Hardy Flyers: Large Heaths are remarkably hardy and can fly on cloudy days, provided the air temperature is at least 14°C.

• Specific Caterpillar Diet: The caterpillars feed exclusively on Hare's-tail cottongrass (Eriophorum vaginatum), which is prevalent in Scottish peatlands.

• Unique Hibernation: Sometimes, particularly in northern colonies, large heaths spend two winters as a caterpillar instead of one, and they can even survive being underwater for a short time.

• Highly Sedentary: These butterflies rarely travel more than a few hundred meters from where they hatch, making them incredibly vulnerable to site destruction.

• High Altitudes: In the Scottish Highlands, they can be found at altitudes as high as 760m.

• Conservation Status: Although doing better in Scotland than in England, they have still declined due to peatland drainage, making Scotch bogs vital to their survival.