I am just getting into the tracing of my ancestors, so please accept this as what it is, which is to say something less than the advice of a real expert. The first census of the entire UK was completed in 1851, or so I am told. The registration of birth records with the civil authorities (as opposed to the churches) began in Scotland perhaps ten years earlier. Prior to this you are dependent on church (Kirk) records, which can be very good indeed but are not available online and have not been indexed into the LDS (Mormon) online archive. I believe that they are available on microfiche through the Mormon Family History Centers. Like all work in this field, there can be surprises. Most lowland scots were Presbyterian, but there were a smattering of (much smaller) Protestant denominations like the Baptists. Births, deaths and marriages were recorded with the Pastor of your congragation. If your ancestor was a Baptist, looking in the Presbyterian Kirk records would be a non-starter. Another complication is that there were changes in the Kirk boundaries over time and people moved. In my clan of Johnstons, Andrew was born in Aberdeen while Robert, Sarah and Christina were born in Galashiels. All four made it into the civil birth registry. I was told flatly by my Grandmother that her father-in-law, Robert William Johnston, was a Presbyterian, so when I attack the Kirk records that is where I am going to start - that is to say, the Presbyterian Kirk records for Galashiels and Aberdeen.