Just in case anyone is wondering as to why Ireland have two songs, the first one (Amhrán Na bhFiann) is the Irish national anthem, however, since Ireland plays as a united island in rugby, this doesn't represent the Northern Ireland which is separate and is part of the UK. In Soccer there are separate teams (Republic of Ireland and Northern Ireland), but in hockey, rugby and cricket, there's just Ireland.
So, they commissioned Phil Coulter to write Irelands Call to have an anthem that can be representative of the whole team. When we play at home, we play both Amhrán Na bhFiann and Irelands Call, but when we're away, we just play Irelands Call.