You do not mention where in Ireland he came from, nor his religion,
and at this distance in time it is impossible to know why, but there
are a number of possible reasons and some have to do with the history
of Ireland and Scotland and the religious divide between Catholic and
Protestant. The background reading below should assist you.
First, let me just say that the census returns are not always a
accurate. For example, from my own experience of researching my family
history I can say that my great grandfather?s place of birth were
shown as three totally different places, and his ages varied by as
much as 20 years.
The Scotland?s People website gives some information on how the census
?Information given in the census can be inaccurate ? age, place of
birth, even recorded relationship to head of household can all be
unreliable, either by accident or by design. For example, sometimes a
person did not know their correct age or was not always honest about
Secondly you say he emigrated to Scotland when he was 5. Perhaps when
he became older he was told by his parents that he was born in
Scotland and was therefore none the wiser.
The emigration date of 1851 is interesting as his family?s decision to
emigrate may have been the result of the effects of the Irish Potato
Famine. This caused the death of perhaps over a million people and the
mass migration of at least two million people to Great Britain, United
States, Canada and Australia.
For preliminary reading, you can find out more on this page.
During the 19th century there was a large number of Irish who
emigrated to Scotland. Many were Catholic and on their arrival were
subject to persecution and prejudice. Some of this historical
prejudice came from the Scottish Protestant occupation of Ulster in
the 17th and 18th centuries. These two pages will give you some
background information. Perhaps your descendants made a decision to
call themselves Scottish to try and overcome this prejudice.
?many Scottish-born descendants of the Irish immigrants would style
themselves "Scottish", while others take pride in their dual
nationality while others spurn any association with the country of
their birth, feeling greater affinity and loyalty to Ireland.?
You may find these additional sources useful reading.
Irish in Scotland
Report from the Scottish Census of 1871
?The immigration of such a number of people from the lowest class and
with no education will have a bad effect on the population. So far,
living among the Scots does not seem to have improved the Irish, but
the native Scots who live among the Irish have got worse. It is
difficult to imagine the effect the Irish immigrants will have upon
the morals and habits of the Scottish people.?
Irish Immigrants and Scottish Society in the Nineteenth and Twentieth Centuries
Tom Devine (1999: 502) states that the Irish Protestant migration to
Glasgow was predominantly from the northern counties of Antrim, Down,
Londonderry and Armagh, and the Catholic migration was from Donegal
and Cavan which are now part of the Republic of Ireland. The majority
of the Irish immigrants from the early wave of migration were
Catholics from Donegal. Many were poor, ill-educated and lacked
industrial skills. Several decades later, a significant number of
Protestant Irish came from the Belfast area, specifically to boost the
production of shipbuilding in the Clyde.
The history of Glasgow. Use the search feature to find out about the
migration of Irish to the city.
I hope this answers your question. If it does not, or the answer is
unclear, then please ask for clarification of this research before
rating the answer. I shall respond to the clarification request as
soon as I receive it.