Bull Island / the North Bull Island is in Dublin Bay, north of the mouth of the River Liffey.
The mainly sand island developed as a result of the presence of the North Bull Wall, built in 1825 on the advice of cartographer and harbour builder Captain Bligh, of HMS Bounty fame.
The island is connected to the shore by an ancient wooden bridge at its SW end, and a road/causeway midway along the island, built in 1962. Much silting of the inner stretch of water has occurred since then, especially close to the causeway, which is now recognised as an environmental monstrosity, and studies are underway to find a solution.
There is an Interpretive Centre near the causeway, built shortly before planning permission became necessary.
Dollymount Strand runs the entire length of the outside of the island; much of the rest is taken up with two golf courses, which are fenced off from the outer rim. Hares abound, and are tolerated with equanimity by the golfers.
The significance of the Bull for bird watchers is in the huge numbers and variety of avian tresidents and visitors. Regular sightings include Golden Plover, Bar-tailed Godwit, Great Northern Diver, Little Egret, Peregrine, Merlin, Short-eared Owl. The island receives internationally important numbers of Brent Geese, Knot, and many other winter species. Living close to buses, cars, golfers, joggers and even dogs, the birds do not startle easily. In the channels, the rising tide concentrates the birds as it pushes them up the shore, and they can be watched from very close range.
The Bull features prominently in the early stages of the education of all Dublin birders. It holds its interest for even the very advanced, because it is always throwing up surprises – rare migrants (I saw an avocet once), and the odd mega-vagrant.