If Tom Devine is correct, your Highland ancestors probably spent a great deal of time working as migrant labor within Scotland during the harvest. Devine estimates that at least one person per family was involved in this labor force. This practice had many advantages for the Highlanders. Primarily, it provided them with the income to survive on their remote homes. Essentially, many families existed on remittances sent home by sons and daughters working in the Lowlands. It slowed depopulation of the Highlands because people had the income to buy what they could not grow. Additionally, people who had temporary moved to the Lowlands were not in the Highlands thus limiting pressure on food resources.
One advantage that Devine doesn’t mention is that all this movement would have increased the networks available to the Highlanders. Increased networks (which is really about more communication) would improve their access to information about jobs and emigration opportunities. To be fair, I don't think network theory was used by any historians in the 1970s.
While Devine does not mention individual Highland migrant workers by name, his article does provide an overview of one aspect of the Highland experience for this period. And undoubtedly, many of you will have examples of migrant laborers in your family trees.
Devine, T.M. “Temporary Migration and the Scottish Highlands in the Nineteenth Century” The Economic History Review, New Series, Vol. 32, Issue 3 (Aug. 1979), 344-359. Access the first page of the article here; see if your local library has a JSTOR subscription so you can read the rest of the article.