Bull Island - Nature

Nature

The island is primarily a sand structure approximately 5 km long and 1 km wide. The southeast facing side is a flat beach, backed by marram-grass-anchored dunes, scrub and marsh. On the northern side of the Bull, between the island and the mainland, is a large linear saltmarsh complex backed by mudflats all of which are covered at high tide. Several of the city's small rivers and streams enter the bay here, notably the Naniken River, the Santry River, Fox Stream, Blackbanks Stream and Daunagh Water. Furthermore, the city's second largest river by volume, the River Tolka, has its estuary facing the city end of the island, into which the Wad River, and a combination of several smaller watercourses, also flow.

Bird life on the island has been protected by legislation since the 1930s, and it was designated a national nature reserve in 1988. It is listed by UNESCO as a biosphere reserve. Bird species on the island include Pale-bellied Brent Geese, Eurasian Curlews, Eurasian Oystercatchers, Grey Plovers Northern Shovelers, Little Egrets, Reed Buntings and Little Terns.. There are six terrestrial mammal species on the island: Brown Rats, Red Foxes, field mice, Irish Hares, hedgehogs and European Rabbits. The hare has been in decline for many years and faces an uncertain future. During a study of hares on the island during the 1990s it was concluded that poor breeding success due to disturbance from people and dogs was the main cause of the drop off in numbers. The rabbit was also once much more numerous than it is today. In 1991 myxomatosis entered the population and caused devastating losses. Shortly after this, in 1992, rabbit hemorrhagic disease was also found in blood samples taken from sick rabbits. Common Seals and Grey Seals are also found in the surrounding waters and can regularly be seen hauled out on sand at low tide at the tip of the island near Howth. Harbour Porpoise can also be seen sometimes out in the bay.

The island is also home to many species of plants including the Bee orchid, Pyramidal orchid and common spotted orchids. There is an interpretative centre at the end of the causeway on the right hand side which has displays and information on the flora and fauna of the island, and there are also information signs to either side of the causeway access, and on the roundabout where the causeway road approaches the beach.