you can order a copy of the birth certificate from general registry - see www.manxnotebook.com/famhist/genealgy/refs.htm
If they stayed on the Island then the 1891 and 1901 censuses should provide some info

There are a number of McCormick familes in the 1881 census (free on line www.familysearch.org) - possibly your ancestor is among them - most heads of households appear to be Irish or Scots born however