Hi: Sorry for delay in replying but just got back from FL. Interestingly, my grandfather was John James Davin and grandmother Catherine but not your Davins I think. I did a quick check of the Irish Family History Foundation (
http://www.rootsireland.ie/) web site and found two records which could be your John Davin. One an 1859 birth record in County Mayo for a John Davin with father Richard and mother Catherine. The second a marriage record in County Tipperary (South) in 1884 for a John Davin with a spouse Kate and father Richard. It costs 5 euros to get a look at these records which you can pay with a credit card. I wonder if any of John and Catherine's children were born in Ireland. If they were and you have their names and approximate dates of birth that might be helpful. Anyway hope this helps. Bill