There was a certain irony that Captain McDonald's perfect French, learned as a result of his Jacobite activities as a rebel against the British Crown, was crucial as the British army under General Wolfe gained a foothold in order to do battle with the French who were entrenched in the City of Quebec.
The French had posted sentries at strategic intervals along the beach below the cliffs west of the town. The first post was passed without incident, but at the second a guard sighted the leading boats and immediately challenged them.
Invisible in the dark hour before the dawn, his sharp Qui vive? came as an unwelcome shock. A quick-witted officer of the Fraser Highlanders, Captain Donald McDonald, who in his time had served the Jacobite cause in France and spoke the language perfectly, answered in a low voice, "La France!" The sentry was insistent: "A quel regiment," he demanded--"De la Reine," McDonald ventured, knowing that part of this battalion was with Bougainville. The sentry, apparently satisfied, did not ask for the password.
A little further on, under the Samos battery, another sentry repeated the challenge and he could just be seen running down to the water within pistol shot. What are you speaking so quietly for, he wanted to know. Provision boats, replied McDonald. Don't make noise or the English will hear us. Again the sentry let them pass. (Source: The Plains of Abraham)
From Loyal Lochaber and its associations, it was noted that Captain MacDonald was slain in Quebec:
The use of Jacobite prisoners in North America was suggested to the British government (see below):