Unique species and wildlife

There has been a great interest in the natural history of St Kilda since the middle of the 19th century. This continues today under the supervision of Scottish Natural Heritage. A research project studying the Soay sheep begun in the 1950s continues today and there have been major surveys of the seabirds on and around the islands.

In more recent years there has been a growing interest in the marine life. The clarity of the water and St Kilda’s remote location has made the archipelago very attractive to divers.


St Kilda is Europe’s most important seabird colony, and one of the major seabird breeding stations in the North Atlantic. The world’s largest colony of gannets nests on Boreray and the sea stacks.

St Kilda mice

Two kinds of mouse used to be found on St Kilda. Both were larger sub-species of the mainland house mouse and wood mouse. The St Kilda house mouse became extinct after the evacuation in 1930. The St Kilda fieldmouse is still common on Hirta and is also present on Dun. It mainly feeds on snails, insects, moss and seeds, but will also feed on the carcasses of dead sheep, birds and any apples, or other delicacies foolishly left around by work party members!

St Kilda wren

The St Kilda wren is a larger sub-species of the mainland wren; there are only a few hundred pairs, making it a great rarity. Specimens of the adult birds and their eggs were highly prized and the St Kildans used to collect eggs for selling to collectors. Today, it’s fully protected on St Kilda.

Soay sheep

All Soay sheep in the world are descended from those found on the island of Soay in the St Kilda archipelago. These small sheep are one of the most primitive forms of domestic sheep in the world and have probably remained virtually unchanged for thousands of years.