Why did britain move the fighting to the southern colonies

With the French now involved, the British, still believing that most Southerners were Loyalists, stepped up their efforts in the Southern colonies. A campaign began in late 1778, with the capture of Savannah, Georgia. Shortly thereafter, British troops and naval forces converged on Charleston, South Carolina, the principal Southern port. They managed to bottle up American forces on the Charleston peninsula. On May 12, 1780, General Benjamin Lincoln surrendered the city and its 5,000 troops, in the greatest American defeat of the war.

But the reversal in fortune only emboldened the American rebels. South Carolinians began roaming the countryside, attacking British supply lines. In July, American General Horatio Gates, who had assembled a replacement force of untrained militiamen, rushed to Camden, South Carolina, to confront British forces led by General Charles Cornwallis. But Gates's makeshift army panicked and ran when confronted by the British regulars. Cornwallis's troops met the Americans several more times, but the most significant battle took place at Cowpens, South Carolina, in early 1781, where the Americans soundly defeated the British. After an exhausting but unproductive chase through North Carolina, Cornwallis set his sights on Virginia.

can you show the map , i'll be able to update my answer

what is the other part to the question