|Meaning of name||Old Norse: moor or mossy island|
A snow shower over Mousa
Mousa shown within the Shetland Islands
|OS grid reference|
|Area||180 hectares (0.69 sq mi)|
|Area rank||115= |
|Highest elevation||55 metres (180 ft)|
|Sovereign state||United Kingdom|
|Council area||Shetland Islands|
Mousa // (Old Norse: Mosey "moss island") is a small island in Shetland, Scotland, uninhabited since the nineteenth century. The island is known for the Broch of Mousa, an Iron Age round tower, and is designated as a Special Protection Area for storm-petrel breeding colonies.
Mousa lies a mile off the east coast of Mainland Shetland in the parish of Dunrossness about 15 miles (24 km) south of Lerwick. Almost divided in two by inlets, East and West Hams, the island is 1.5 miles (2.4 km) long and almost 1-mile (1.6 km) in maximum width. Geologically beds of hard sandstone alternate with muddy limestones that weather to produce fertile soil. A quarry provided flagstones for Lerwick.
Mousa's fertile soil supports a rich diversity of plants, including sheep's-bit and creeping willow in the herb-rich grassland, despite the wind, salt spray and grazing by sheep.
The Norse tended to consider an island to be something that they could circumnavigate, and this included being able to drag a boat over land. Thus Mousa was considered two islands, namely North Isle and South Isle.
Mousa Broch is the best preserved Iron Age fortification in the British Isles. The 2000-year-old round tower stands above a rocky shoreline, one of a pair of brochs guarding Mousa Sound. They may be part of a chain of brochs in this part of Shetland, visible from each other as beacons. The other of the "pair", at Burland on the Mainland is far less well preserved. Many brochs were the focus of a settlement, but there has never been a full archaeological investigation to confirm this at Mousa. It was cleared out in 1860 and 1919. Mousa has survived intact to such a height and is thought to never have been much higher than it is today. It escaped stone gathering for nearby stone walls and croft houses (now ruined).
Mousa is mentioned in the Orkneyinga Saga as being used as a place of defence during invasions, as well as a lovers' hideout.
The entrance passage into Mousa is long, reflecting the enormous thickness of its walls. At its base the broch is 15m in diameter, but the interior is only 6m in diameter. Within the huge thickness of the base of the walls are a range of chambers probably used for storage, while at higher levels passages run between the inner and outer skins of the wall. On the inside a steep flight of steps leads to the top of the wall. Halfway up is a landing which probably gave access to an upper level of the interior of the broch, built on a ledge running around the circumference of the interior.
Mousa holds c. 6,800 breeding pairs of European storm-petrels in total. This represents about 8% of the British population and 2.6% of the world population. The island has been designated as both a Special Protection Area (SAC) and a Site of Special Scientific Interest (SSSI) by Scottish Natural Heritage, and is run as a reserve by the RSPB.
The seas surrounding the island are host a population of sandeel that provides a food source for many species fish, seabirds, seals, whales and dolphins: the area is considered to have the most reliable population of sandeels of all the seas surrounding Shetland. These seas are therefore also protected, forming both a Special Area of Conservation (SAC) and a Nature Conservation Marine Protected Area (NCMPA).
Storm petrels may also be found at the reserve of Haaf Gruney.
- Haswell-Smith, Hamish (2004). The Scottish Islands. Edinburgh: Canongate. pp. 411–14. ISBN 978-1-84195-454-7.
- Area and population ranks: there are c. 300 islands over 20 ha in extent and 93 permanently inhabited islands were listed in the 2011 census.
- Ordnance Survey. OS Maps Online (Map). 1:25,000. Leisure.
- Anderson, Joseph (Ed.) (1893) Orkneyinga Saga. Translated by Jón A. Hjaltalin & Gilbert Goudie. Edinburgh. James Thin and Mercat Press (1990 reprint). ISBN 0-901824-25-9
- "Mousa Reserve guide" (PDF). RSPB. Archived from the original (pdf) on 2007-08-08. Retrieved 2007-12-10.
- "Overview of Mousa". Gazetteer for Scotland. Retrieved 2007-12-10.
- "Broch of Burland". canmore (database). Historic Environment Scotland. Retrieved 21 September 2017.
- "Mousa Broch". Undiscovered Scotland. Retrieved 2007-12-09.
- Thomas, D. (2011). "An Investigation of Aural Space inside Mousa Broch by Observation and Analysis of Sound and Light". www.intarch.ac.uk (30).
- "Mousa". RSPB. Retrieved 2007-12-10.
- Ratcliffe, N.; Vaughan, D.; White, M. (1998). "The status of Storm Petrels on Mousa, Shetland". Scottish Birds. 19: 154–159.
- Harrop, Hugh; Tipling, David (2002). "The Storm Petrels of Mousa". Birding World. 15 (8): 332–333.
- "SAC Standard Data Form" (pdf). JNCC. Retrieved 2007-12-10.
- "Mousa SSSI". Scottish Natural Heritage. Retrieved 21 November 2019.
- "Mousa to Boddam Marine Protected Area Summary". Scottish Natural Heritage. Retrieved 21 November 2019.
- "Mousa SAC". Scottish Natural Heritage. Retrieved 21 November 2019.
- "Mousa to Boddam MPA(NC)". Scottish Natural Heritage. Retrieved 21 November 2019.