Rockabill () is a close pair of islands (Rock and Bill) in the western

Irish Sea The Irish Sea is a body of water that separates the islands of Ireland and Great Britain. It is linked to the Celtic Sea in the south by St George's Channel and to the Inner Seas off the West Coast of Scotland in the north by the North Ch ...

about 6 kilometres east-north-east of

Skerries A skerry is a small rocky island, usually defined to be too small for habitation. Skerry, skerries, or The Skerries may also refer to: Geography Northern Ireland *Skerries, County Armagh, a List of townlands in County Armagh#S, townland in Coun ...

County Dublin County Dublin ( or ) is a Counties of Ireland, county in Republic of Ireland, Ireland, and holds its capital city, Dublin. It is located on the island's east coast, within the Provinces of Ireland, province of Leinster. Until 1994, County Dubli ...

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. The two granite islands are separated by a channel about 20 metres wide. On the Rock there is a

lighthouse A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Ligh ...

, built 1855–1860 from

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

and

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

and automated in 1989, and several walls and outbuildings.

Environment

The walled areas of the Rock have enabled a build-up of soil and the establishment of vegetation, notably tree mallow (''

Malva arborea ''Malva arborea'' (previously known as ''Lavatera arborea'', or, more recently as ''Malva eriocalyx''), the tree mallow, is a species of mallow native to the coasts of western Europe and the Mediterranean region, from Ireland and Britain south t ...

''), which provides nesting cover for the birds. The Bill is smaller and has very little vegetation. Rockabill is an important

seabird Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...

breeding island, especially notable for its

tern Terns are seabirds in the family Laridae, subfamily Sterninae, that have a worldwide distribution and are normally found near the sea, rivers, or wetlands. Terns are treated in eleven genera in a subgroup of the family Laridae, which also ...

s. It is an internationally important site for

roseate tern The roseate tern (''Sterna dougallii'') is a species of tern in the family Laridae. The genus name ''Sterna'' is derived from Old English "stearn", "tern", and the specific ''dougallii'' refers to Scottish physician and collector Dr Peter McD ...

s, with the largest colony in Europe, 1,597 pairs, and 2,085 pairs of Common Terns (2017 data). Other seabirds include

black guillemot The black guillemot or tystie (''Cepphus grylle'') is a medium-sized seabird of the Alcidae family, native throughout northern Atlantic coasts and eastern North American coasts. It is resident in much of its range, but large populations from the ...

s and black-legged kittiwakes. It has been designated an

Important Bird Area An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations. IBA was developed and sites are identified by BirdLife Int ...

(IBA) by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

because of its seabird colonies. Rockabill Lighthouse is owned by the

Commissioners of Irish Lights The Commissioners of Irish Lights (), often shortened to Irish Lights or CIL, is the body that serves as the general lighthouse authority for Northern Ireland and the Republic of Ireland and their adjacent seas and islands. As the lighthouse a ...

and is a Refuge for Fauna and a

Special Protection Area A special protection area (SPA) is a designation under the European Union Directive on the Conservation of Wild Birds. Under the Directive, Member States of the European Union (EU) have a duty to safeguard the habitats of migratory birds and cer ...

under the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...

Birds Directive. Since 1989, when the protection afforded by the lighthouse keepers ceased, the islands have been managed by

BirdWatch Ireland BirdWatch Ireland (BWI) is a voluntary conservation organisation and registered charity devoted to the conservation and protection of wild birds and their habitats in Ireland. It was formerly known as the Irish Wildbird Conservancy (IWC). Irish Wi ...

. The sea area between Rockabill and

Dalkey Island Dalkey Island ( ) () is an island for which the nearby village of Dalkey is named ( meaning "thorn island", with ''ey'' the Old Norse (Viking) version of "island"). It is an uninhabited island located in the county of Dún Laoghaire-Rathdown, ...

has recently been proposed as a

Special Area of Conservation A special area of conservation (SAC) is defined in the European Union's Habitats Directive (92/43/EEC), also known as the ''Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora''. They are to protect the 220 habitats and ap ...

References

{{refend Islands of County Dublin Important Bird Areas of Atlantic islands Important Bird Areas of the Republic of Ireland Uninhabited islands of Ireland