Bull Island, with its 5.63km of beach, two golf courses and world famous bird sanctuary was created by the building of the Port's two walls & the Great South Wall and the North Bull Wall.
A small island built up over 200 years as a result of the construction of the north harbour wall of Dublin Port, it has an adjoining foreshore of sandy beaches, dunes, saltmarshes and mudflats. It is connected to the land by a wooden bridge and a more recently constructed causeway. The site is unique in Ireland because it supports well-developed saltmarsh and dune systems displaying all stages of development from the earliest phase of colonisation to full maturity. Its location as a UNESCO Biosphere reserve within a capital city is also unique and it is classified as a Wetland of International importance under the Ramsar Convention.
The area is important for numerous species of wintering waterbirds and waders. For the birdwatcher the most interesting areas are the tidal flats and salt marsh between the island and the mainland. It hosts internationally important numbers of Brent Geese which can often be found grazing on the grass alongside the coast road. In recent years they have spread to parklands and football fields back in from the coast.
There are large flocks of Shelduck, Widgeon and Teal. The north-east end of the causeway is good for Pintail, while Shoveler usually stay south of the causeway. The deeper water at either end of the island has Goldeneye and Red-breasted Merganser.