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• Text account
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• Reference and further resources

The site was identified as important in 2007 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.

Populations meeting IBA criteria ('trigger species') at the site:

Species	Red List1	Season	Year(s)	Size	IBA criteria
European Storm-petrel Hydrobates pelagicus	LC	breeding	2006	1,398 breeding pairs	B2, C2, C6
European Shag Gulosus aristotelis	LC	breeding	2006	1,296 breeding pairs	A4i, B1i, B3, C3
Ruddy Turnstone Arenaria interpres	NT	winter	1984-1985	940 individuals	A4i, B1i, C3
Lesser Black-backed Gull Larus fuscus	LC	breeding	2006	3,335 breeding pairs	A4i, B1i, B3, C3
Great Black-backed Gull Larus marinus	LC	breeding	2006	901 breeding pairs	B3
Common Tern Sterna hirundo	LC	breeding	1999	96 breeding pairs	C6
Common Tern Sterna hirundo	LC	breeding	2006	78 breeding pairs	C6

1. The current IUCN Red List category. The category at the time of the IBA criteria assessment (2007) may differ.

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2007. The most recent assessment (2007) is shown below.

State (condition of the trigger species' populations)
Species	Reference	Actual	Units	% remaining	Result
European Storm-petrel Hydrobates pelagicus	2,130	1,398	breeding pairs	66	unfavourable
European Shag Gulosus aristotelis	1,200	1,296	breeding pairs	100	favourable
Lesser Black-backed Gull Larus fuscus	3,760	3,335	breeding pairs	89	near favourable
Great Black-backed Gull Larus marinus	1,000	901	breeding pairs	91	favourable
Roseate Tern Sterna dougallii	5	0	breeding pairs	0	very unfavourable
Common Tern Sterna hirundo	105	78	breeding pairs	75	near favourable

Pressure (threats to the trigger species and/or their habitats)
Threat	Timing	Scope	Severity	Result
Invasive and other problematic species and genes	happening now	majority/most of area/population (50-90%)	moderate to rapid deterioration	high
Human intrusions and disturbance	happening now	some of area/population (10-49%)	slow but significant deterioration	medium

Response (conservation actions taken for the trigger species and/or their habitats)
Protected areas	Management plan	Other action	Result
Whole area of site (>90%) covered by appropriate conservation designation	A management plan exists but it is out of date or not comprehensive	Substantive conservation measures are being implemented but these are not comprehensive and are limited by resources and capacity	medium

Year	Protected Area	Designation	% overlap with IBA
1974	Isles of Scilly	Heritage Coast	100
1976	Isles of Scilly	Area of Outstanding Natural Beauty	100
1986	Castle Down (Tresco)	Site of Special Scientific Interest (UK)	10
1986	Gugh	Site of Special Scientific Interest (UK)	7
1986	Samson (With Green, White, Puffin & Stony Islands)	Site of Special Scientific Interest (UK)	7
1986	Shipman Head & Shipman Down (Bryher)	Site of Special Scientific Interest (UK)	7
1986	Chapel Down (St, Martin'S)	Site of Special Scientific Interest (UK)	6
1986	Wingletang Down (St, Agnes)	Site of Special Scientific Interest (UK)	3
1986	Eastern Isles	Site of Special Scientific Interest (UK)	6
1986	St, Helen's (With Northwethel & Men-A-Vaur)	Site of Special Scientific Interest (UK)	3
1986	Annet	Site of Special Scientific Interest (UK)	3
1986	Great Pool (Tresco)	Site of Special Scientific Interest (UK)	2
1986	Plains & Great Bay (St, Martin'S)	Site of Special Scientific Interest (UK)	2
1986	Tean	Site of Special Scientific Interest (UK)	2
1986	Lower Moors (St, Mary'S)	Site of Special Scientific Interest (UK)	1
1986	Rushy Bay & Heathy Hill (Bryher)	Site of Special Scientific Interest (UK)	1
1986	Norrard Rocks	Site of Special Scientific Interest (UK)	1
1986	Big Pool & Browarth Point(St, Agnes)	Site of Special Scientific Interest (UK)	1
1986	Pool Of Bryher & Popplestone Bank (Bryher)	Site of Special Scientific Interest (UK)	1
1986	Western Rocks	Site of Special Scientific Interest (UK)	<1
1987	Higher Moors & Porth Hellick Pool (St, Mary'S)	Site of Special Scientific Interest (UK)	2
1989	Peninnis Head (St, Mary'S)	Site of Special Scientific Interest (UK)	2
1989	White Island (Off St, Martin'S)	Site of Special Scientific Interest (UK)	2
1989	Porth Seal (St, Martin'S)	Site of Special Scientific Interest (UK)	<1
1995	Pentle Bay, Merrick and Round Islands	Site of Special Scientific Interest (UK)	8
1996	Isles Of Scilly Complex	Site of Community Importance (Habitats Directive)	33
1996	St, Martin's Sedimentary Shore	Site of Special Scientific Interest (UK)	6
1996	Porthloo	Site of Special Scientific Interest (UK)	<1
1996	Watermill Cove	Site of Special Scientific Interest (UK)	-
2001	Isles of Scilly	Special Protection Area (Birds Directive)	72
2001	Isles of Scilly	Ramsar Site, Wetland of International Importance	72
2005	Isles of Scilly Complex	Marine Protected Area (OSPAR)	16
2013	Isles of Scilly Sites	Marine Conservation Zone	12
2014	Isles of Scilly	Marine Protected Area (OSPAR)	11

Habitat1	Habitat detail	% of IBA
Marine Coastal/Supratidal		major (>10)
Marine Intertidal		major (>10)
Marine Neritic		major (>10)
Grassland	Mesophile grasslands	minor (<10)
Shrubland	Heathland	minor (<10)
Wetlands (inland)	Standing freshwater	minor (<10)

1. IUCN Habitat classification.

Land use	% of IBA
tourism/recreation	-

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Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Isles of Scilly (United Kingdom). Downloaded from https://datazone.birdlife.org/site/factsheet/isles-of-scilly-iba-united-kingdom on 23/11/2024.