On advice of @efgen I am splitting this question into two - one for New York and [one for Panama](http://genealogy.stackexchange.com/q/1554/70), but am leaving the same detail for both because the fact that he was in both geographic areas may help solve the mystery.

**Please only provide Answer(s) for New York here.**

I have a Scottish ancestor, William Sellars born 1820, who had three sons born abroad:

 - Robert John Steven in Albany, New York, USA on 3 Jan 1854
 - William in New York City, USA in about 1857
 - John in Panama, South America in about 1863

He also had two other children born in Scotland 1850 & 1866, and although there are Census records of his children and wife, Margaret (nee Clacher) living back in Scotland, there is nothing to indicate that he ever returned.

His census occupation is given as ship's carpenter but the family story is that he (and his wife, which is not correct) died when he was working on the Niagara Falls so he may have been in the US and Panama working on engineering projects.

I have a World subscription to Ancestry.com but so far have not been able to find any birth or death records in USA or Panama for his sons or him.

Any help on where I might try next greatly appreciated.