Amanda,
I have Colosky ancestors from Michigan, where I have found numerous Coloskys both related and unrelated. Exactly where was your father born in Michigan?
The Coloskys that I am related to spent at least 2 generations in Ontario before emmigrating to Michigan in the mid to late 1800s. Record keeping in Canada during the period in which they arrived at/lived in Canada is very sketchy. The only thing that I can find that mentions ethnic origin (or pertains to it) is for Benjamin Colosky, my Great-great-Grandfather, b 19 Sep 1822 in Huron County, Ontario, d. 8 Feb 1909 in Gilmore Township, Isabella County. On the 1851 and 1871 censuses in Ontario, he is noted as being a Lutheren. I would trust this as accurate--the Canadians were diligent in tracking church affiliation. In the 1851 census, it does not ask for ethnicity, but in the 1871 census, his ethnic origin is specified as Ireland. A Lutheran from Ireland seems highly suspect, but if you read up on the history of the Lutheran Church, it has had a small but continuous presence in Ireland since the 17th century, with many pastors coming from Germany. An obvious place to start looking is through the Lutheran Church in Ireland. It could very well be that the Coloskys in Ireland originally were from Germany! I have recently found this out and have not had the opportunity to check this source.
Let me know if this helps and/or if you find out anything.