|Native name: Ynys Gwales|
|Area||10.72 ha (26.5 acres)|
|Highest elevation||42 m (138 ft)|
Grassholm (Welsh: Gwales or Ynys Gwales) is a small uninhabited island situated 13 kilometres (8 mi) off the southwestern Pembrokeshire coast in Wales, lying west of Skomer. It is the westernmost point in Wales other than the isolated rocks on which the Smalls Lighthouse stands, and is known for its huge colony of northern gannets. Grassholm has been owned since 1947 by the Royal Society for the Protection of Birds, and is one of its oldest reserves. It reaches 42 metres (138 ft).
Grassholm National Nature Reserve is the third most important site for gannets in the world, after two sites in Scotland; St Kilda and Bass Rock. It serves as a breeding site for 39,000 pairs of the birds, and supports around 10 percent of the world population. The turbulent sea around Grassholm also provides good feeding ground for porpoises and bottlenose dolphins.
The island has a significant problem with marine plastic, brought to the island by breeding gannets, as nesting material which the birds have mistaken for seaweed floating in the surrounding waters. The problem has been ongoing through twelve years of RSPB conservation to 2017, and surveys have indicated that 80% of nests contain waste plastics.
Geologically, the island is largely formed from keratophyre though the northwest coast and islet of West Tump are formed from basalt. A couple of NE-SW aligned faults cross the island. Raised beaches are present in places.
Grassholm has been identified with Gwales, an island featured in the Mabinogion. In the Second Branch of the Mabinogi, Gwales is the site of a fabulous castle where the severed head of Brân the Blessed is kept miraculously alive for eighty years while his companions feast in blissful forgetfulness.
Problems playing this file? See media help.
- "SPA Description - Grassholm". Joint Nature Conservation Committee. DEFRA. Retrieved 2 March 2017.
- Anon. "Grassholm". RSPB wepages. The Royal Society for the Protection of Birds. Retrieved 11 April 2010.
- "Saving the birds ensnared on 'plastic island'". Euronews. 20 October 2017. Retrieved 20 October 2017.
- "Gannets ensnared by twisted plastic around their legs on Grassholm island". Sky News. 20 October 2017. Retrieved 20 October 2017.
- "Plastic Gannets". Autumnwatch. 19 November 2014. BBC. BBC2. Retrieved 20 October 2017.
- British Geological Survey 1978 1:50,000 scale geological map sheet (England and Wales) 226/227 Milford (Keyworth, Notts)
- "Branwen ferch Lyr: The Second Branch of the Mabinogi". www.mabinogi.net.
- The Mabinogion: Branwen the Daughter of Llyr, translated by Lady Charlotte Guest. Online at www.sacred-texts.com.
- Mitchell, W H, and Sawyer, L A (1995). The Empire Ships. London, New York, Hamburg, Hong Kong: Lloyd's of London Press Ltd. ISBN 1-85044-275-4.
- "History". Angle Lifeboat Station. Retrieved 30 May 2010.
|Wikimedia Commons has media related to Grassholm.|