plotted by Conor O'Brien and other members of the Arts Club. Periods of greater activity were noted in 1942–1944, with the "old" Irish Mountaineering Club (IMC), from 1948, with the "new" IMC, and from 1978. The most prolific routes were developed on the Steer (the "outer stack"), the "inner stack" facing it, and an isolated pinnacle SW of the Steer, as well as the principal cliff area. Some routes are no longer accessible due to shifts in the rock formations, guano build-up and bird population growth, notably on the Steer. Climbing during the seabird nesting season of April to July is discouraged. Sources External links Birdwatch Ireland Howth Islands of County Dublin Uninhabited islands of Ireland Towers in the Republic of Ireland Climbing areas of Ireland Special Areas of Conservation in Ireland Special Protection Areas in the Republic of Ireland Important Bird Areas of the Republic of Ireland