What were British soldiers looking for in Boston and what did they find

During the evening of March 4, Major General John Thomas, under orders from Washington, secretly led a force of 800 soldiers and 1,200 workers to Dorchester Heights and began fortifying the area. To cover the sound of the construction, American cannons, besieging Boston from another location, began a noisy bombardment of the outskirts of the city. By the morning, more than a dozen cannons from Fort Ticonderoga had been brought within the Dorchester Heights fortifications. British General Sir William Howe hoped to use the British ships in Boston Harbor to destroy the American position, but a storm set in, giving the Americans ample time to complete the fortifications and set up their artillery. Realizing their position was now indefensible, 11,000 British troops and some 1,000 Loyalists departed Boston by ship on March 17, sailing to the safety of Halifax, Nova Scotia.

Explanation:

d. migration