Gweal viewed from Bryher
Norrard Rocks shown within Isles of Scilly
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The Norrard (Northern) Rocks are a group of small uninhabited granite rocks in the north–western part of the Isles of Scilly, to the west of Bryher and Samson. In 1971 they wee designated as a Site of Special Scientific Interest (SSSI) for their breeding seabird colonies and they are permanently closed to landings from boat passengers. The vegetation on the islands is limited by the extreme exposure and only six species of flowering plants have been recorded.
The islands are largely managed as nature reserves by the Isles of Scilly Wildlife Trust, principally for breeding seabirds and grey seals (Halichoerus grypus). The only breeding sites for European Storm–petrel in England are on the Isles of Scilly with eleven colonies and an estimated 1475 occupied sites (i.e. breeding pairs). There are only three small breeding colonies on the Norrard Rocks; Mincarlo, Illiswilgig and Castle Bryher with a total of 37 pairs. Other seabirds breeding within the SSSI are Fulmar (Fulmarus glacialis), Guillemot (Uria aalge), Lesser Black–backed Gull (Larus fuscus) and Herring Gull (L argentatus). The rove beetle (Omalium allardi) has been recorded on several of the islands.
Individual islands and rocks
The islands and rocks are listed below in decreasing order of area.
Gweal is a small rocky island consisting of two hills linked by a boulder beach, just off the west coast of Bryher and is an occasional pupping site for grey seal. Plants recorded are sea beet (Beta vulgaris subsp. maritima ), rock sea–spurry (Spergularia rupicola), common scurvygrass (Cochlearia officinalis), thrift (Armeria maritima) and tree mallow (Lavatera arborea).
Scilly Rock is just over 1 kilometre (0.62 mi) west of Bryher is a large rock, divided by a deep chasm into two parts with a maximum height of 22 metres (72 ft). Each part has a summit named North Cuckoo and South Cuckoo. Landing is difficult and only possible in calm conditions. It is reputedly the island from which the rest of the archipelago gets its name although there is no evidence or explanation for this. Puffin (Fratercula arctica) breed and the only plants recorded are rock sea-spurrey and oraches (Atriplex) species.
Mincarlo is the southernmost of the group 2 kilometres (1.2 mi) west of Samson. Several species nest on the island including the largest breeding colony of Cormorant (Phalacrocorax carbo) in the Isles of Scilly as well as Puffin, Great Black–backed Gull (Larus marinus), Razorbill (Alca torda) and Common Shag (Phalacrocorax aristotelis). The breeding colony of European Storm–petrel (Hydrobates pelagicus) occupied 17 sites during the Seabird 2000 survey. Tree mallow, orache, common scurveygrass, rock sea–spurrey and sea beet have all been recorded. The rocks are a main pupping site for grey seal (Halichoerus grypus). The Arachnologist, W S Bristow visited the Isles of Scilly in 1928, 1929 and 1934 and landed on many of the uninhabited islands. On Mincarlo he recorded the following spiders; Trochosa terricola, Oedothorax fuscus, Lepthyphantes tenuis, Dismodicus bifrons, Xysticus kochi and Halorates reprobus which is associated with the nests of seabirds, especially cormorant and shag.
Several species have bred on Illiswilgig, including a small colony of only three pairs of European Storm–petrel, recorded during the Seascape 2000 survey. Plants recorded are tree mallow, thrift, sea beet, rock sea–spurrey, common scurvy grass, orache and English stonecrop (Sedum anglicum). Illiswilgig is a main pupping and haul–out site for grey seal.
Only a few gulls breed on Maiden Bower and no plants have been recorded.
The Seabird 2000 survey recorded 17 occupied sites of European Storm–petrel. Puffin and gulls also breed on the island and plants recorded are tree mallow, sea beet, rock sea-spurrey, common scurvygrass and orache.
An important breeding and haul out site for grey seal and orache is the only plant recorded.
- "Norrard Rocks". Natural England. 17 December 1986. Retrieved 20 December 2011.
- P Ian Mitchell, Stephen F Newton, Norman Ratcliffe and Timothy E Dunn. "Seabird Populations of Britain and Ireland: results of the Seabird 2000 census (1998-2002).". London: T and A.D. Poyser. Retrieved 15 November 2012.
- Parslow, Rosemary (2007). The Isles of Scilly. London: HarperCollins. ISBN 978-0-00-220150-6.
- North, J. W. (1850). A Week in the Isles of Scilly. London: Longman & Co.
- Bristowe, W S (1935). "Further notes on the spiders of the Scilly Islands". Proc.zool.Soc.Lond.: 219–32.
Media related to Norrard Rocks at Wikimedia Commons