I research the Irish Family History Foundation's database. It contains 12,000,000 surviving rcds for abt 65% of Irish counties. Rcds are increasingly sparse B4 1840, rare B4 1800.
Note 1 - Without a KNOWN county, the chance of an ancestor's rcds NOT being in this database is AT LEAST 35%.
Note 2 - Only 1/2 of Co. Cork's rcds are in this database.
Note 3 - The RC church kept control over most parish rcds from Tipperary (north). These are ONLY available thru the Tipperary Family History Research center at a substantial fee (regardless of outcome).
For John Hoban B 1897 +/- 1 yrs, Ardagh RC parish, Co. Mayo, with the father's forename unknown, I found 1 rcd in 1896. The father's forename was Martin.
However, I can't find B rcds for Michael, Patrick, Peter, Mary or Annie in the same Mayo parish, or consistently within other Mayo parishes. This casts doubt on the veracity of John's rcd.
B/M/D registration was civil after 1863 and supposedly comprehensive. Civil rcds which survived the 1922 Four Courts fire should be in this database. In this case, they aren't. This infers the rcds didn't survive or haven't been transcribed. For civil rcds, contact the General Register Office at http://www.groireland.iehttp://www.groireland.ie for certificate copies. Fees apply.
Google the Foundation's name to lead you to this database. Register, opt to be notified as rcds are added and browse. Pls post your search results to my genforum msg.