Eastern Isles

Also within

Cornwall County Isles Of Scilly Scenic Area

Condition (Natural England)

Habitats

Bracken scrub

Geology & landscape

Rock Type: Granite

Landscape processes: Volcanic / Igneous

Birds & fish recorded

Birds

Description

Area, approx 83.8 hectares Description The Eastern Isles are located on the north eastern side of the Isles of Scilly archipelago immediately to the south east of St. Martin’s. The site includes the uninhabited islands of great Ganilly, Little Ganilly, great Arthur, Little Arthur, Nornour, great Ganinick, great Innisvouls and Menawethan together with a number of smaller adjacent islets and rocks. All of the islands are composed of coarse grained Hercynian granite with some small areas of wind blown sand and linking cobble beaches. Although the islands are partially sheltered from extreme westerly gales, their low altitude, maritime exposure and thin podzolic soils have resulted in a depleted flora. great Ganilly, the largest and highest island covering some 13 hectares and reaching a height of some 34 metres, has 74 recorded plant species out of a species list of 111 for the whole of the Eastern Isles. Of particular note is the nationally rare orange bird’s foot Ornithopus pinnatus that occurs in the small area of maritime heathland dominated by bell heather Erica cinerea on the northern side of great Ganilly. The steep slopes of the islands are dominated by bracken Pteridium aquilinum and bramble Rubus fruticosus whilst many of the lower outer margins are fringed with maritime grassland where thrift Armeria maritima and sea beet Beta vulgaris sp maritima are abundant. Small areas of blown sand linking great, Middle and Little Arthur support stands of marram grass Ammophila arenaria. Sea kale Crambe maritima occurs in the back shore zone between Nornour and great Ganilly. Other uncommon plants on the islands include white ramping fumitory Fumaria capreolata and sea radish Raphanus maritimus, together with the nationally rare balm leaved figwort Scrophularia scorodonia and shore dock Rumex rupestris. great Ganinick is the only island on Scilly, apart from Tresco, where oak Quercus robur has been recorded. Butcher’s broom Ruscus aculeatus also occurs here and on Nornour, perhaps associated with the previous Roman occupation and settlement. The islands support eight species of breeding sea birds including large colonies of greater black backed gull Larus marinus, lesser black backed gull L. fuscus, herring gull Larus argentatus and shag Phalacrocorax aristotelis. There are smaller colonies of razorbill Alca torda, cormorant Phalacrocorax carbo, fulmar Fulmarus glacialis and a few puffin Fratercula arctica. The Eastern Isles also provide isolated habitats for an important breeding colony of grey seal Halichoerus grypus. Site Notified to the Secretary of State on 5 December 1986

Species mentioned

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.

Plant communities