I have posted messages in the Ireland section and received terrific information from Michael Ronayne who wrote:
Pat, I now believe that I understand what was occurring in your family. During the English occupation of Ireland, there was intensive pressure to Anglicize Gaelic surnames. This process ranged from a letter by letter substitution of the Gaelic alphabet into the English alphabet, to a literal translation of the meaning of the name into English. In the case of literal translations, all reference to the original Gaelic surname could easily become lost. Starting with the same Gaelic surname, which may already have had several pronunciations in different parts of Ireland, a wide range of translations and variations occurred, which at first glance appear to be unrelated. In the beginning of the 20th century a number of Irish linguists started comprehensive studies of Irish surnames. These studies were expanded after the Irish revolution. One of the linguists, who devoted 25 years of his life to this study was Fr. Patrick Woulfe a Priest of the Diocese of Limerick, who published a book entitled “Irish Names and Surnames” in 1922. While others and I, have found errors in Woulfe’s work, thanks in large part to computer tools, which Woulfe did not have, the book is still of monumental value to Irish genealogical research.
What made the process of documenting Irish surnames so difficult was that it was not uncommon to find the same surname spelled differently depending on who was providing the information and who was recording that information. It was also quite common for spelling errors to be introduced into the recorded surnames. For example, in the family of my wife’s great-great grandmother I found (thanks to a very alert church secretary) her baptismal certificate recorded as Mannin and not Manning as the rest of the family was recorded. If you did not know that Mannin and Manning were variations of the Gaelic surname O’Mainnin you would tend to ignore the record. I am still missing records for this family line, but now that I know that there was is a chance that the Mannin form of the surname could have been used, I plan to reexamine the records for this version of the surname. It was also quite common for the public given name and surname to be English and while the names used within the family, or the pet names, were Irish.
I suspect that a similar thing occurred in your family. You provided three versions of the surname, which were in decreasing order of confidence: Mulhare, Mulkear & McHeir. Only the surname Mulhare is clearly identifiable as an Irish surname, which is documented in Woulfe’s book. Here is what he had to say about it:
O’Maoilcéire –I– O’Mulchery, O’Mulkery, O’Mulcheir, O’Mulkere, Mulkerry, Mulcair, Mulhare, Wilhere, Wilhair; ‘descendant of Maolcéire’ (servant of St. Ciar). This surname probably originated in Co. Galway where it was most common in the 16th century. It was current at the same period in Clare, Limerick, Tipparary and Donegal. For Wilhair, the anglicized form in the last-named county, compare Vaughan for Maughan.
The surname variation O’Mulkere, without the “O” prefix, and Mulcair would be phonetically very similar if not identical to Mulkear, which I now suspect is just a spelling error. McHeir is not to be found in Griffith’s Valuation or Woulfe’s book and I suspect that is a gross error with a similar sound. Note that while Woulfe documents the name as originating in Co. Galway in the 16th century, Griffith’s Valuation shows that the name occurred in both Galway and Roscommon in about the same numbers in the middle of the 19th century.
Good luck in your search and keep us all posted on your results for Bartholomew Mulhare in Co. Roscommon.