The glacial channel which follows the fault is marked by a distinctive inland valley across the Head which was fed by rainwater from the high ground on both sides and formed a boggy area which drained into the sea.

A dam was built to form a freshwater loch to be used for angling and waterfowl hunting, a nine-hole golf course was also constructed nearby.

[3][4] Today Mire Loch is a valued part of St. Abbs Head National Nature Reserve providing a home for freshwater birds such as little grebe, reed bunting, heron, mute swan, moorhen and sedge warbler.

The fringing vegetation which is composed mostly of high reeds provides shelter and food for nesting birds as well as for migrants in spring and autumn.

In recent years the NTS has planted almost 1000 trees around the loch in an effort to provide extra cover for migrant birds.