UK033
Isles of Scilly


IBA Justification

The site was identified as internationally important for bird conservation 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 List Season (year/s of estimate) Size IBA criteria
European Storm-petrel Hydrobates pelagicus LC breeding (2006) 1,398 pairs B2, C2, C6
European Shag Gulosus aristotelis LC breeding (2006) 1,296 pairs A4i, B1i, B3, C3
Ruddy Turnstone Arenaria interpres NT winter (1984–1985) 940 birds A4i, B1i, C3
Lesser Black-backed Gull Larus fuscus LC breeding (2006) 3,335 pairs A4i, B1i, B3, C3
Great Black-backed Gull Larus marinus LC breeding (2006) 901 pairs B3
Common Tern Sterna hirundo LC breeding (1999) 96 pairs C6
Common Tern Sterna hirundo LC breeding (2006) 78 pairs C6

IBA Conservation

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.

IBA conservation assessment
Year of assessment State Pressure Response
2007 very poor high medium
Whole site assessed? State assessed by Accuracy of information
yes population good

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

Pressure (threats to the trigger species and/or their habitats)
Threat Timing Scope Severity Result
Invasive and other problematic species and genes happe­ning now most of popul­ation/area (50–90%) moderate decline (10–30% over 3 gener­ations) high
Human intrusions and disturbance happe­ning now some of popul­ation/area (10–49%) slow decline (1–10% over 3 gener­ations) medium

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90%) covered by appropriate conservation designation A management plan exists, but it is out of date or not compre­hensive Substantive conservation measures are being implemented, but these are not compre­hensive and are limited by resources and capacity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

IBA Protection

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

Habitats

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

Land use

Land use % of IBA
tourism/recreation -


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 23/12/2024.