Sika deer
Fallow deer were introduced in Norman times, and now have a population of about 10,000. Sika deer were introduced in Powerscourt park in 1860, escaped from captivity, and now number about 20,000. Scottish roe deer were introduced to the Lissadell Estate in Co. Sligo around 1870 by Sir Henry Gore-Booth. The Lissadell deer were noted for their occasional abnormal antlers and survived in that general area for about 50 years before they died out, and few roe deer currently exist in Ireland.