From Bermuda, Parker joined the British forces in the Chesapeake Bay under Admiral Sir George Cockburn and took part in the blockade of Baltimore. A bold and efficient commander, he became known for his ferocity in destroying American farms and property along the Chesapeake. Having for several days raided Kent County, Maryland, he landed a shore party and attempted a night attack on a detachment of Maryland militia at Fairlee, Maryland on the night of 30 August 1814. Parker, who had recently liberated four slaves after raiding the plantation of Richard Frisby, was told by one slave that there was an American militia unit nearby. Parker landed the "Menelaus" at Tolchester, Maryland and had the slave guide him to the position. There he met resistance from the 21st Maryland Militia under command of Lt. Colonel Phillip Reed in the corn field of Isaac Caulk. This precipitated the Battle of Caulk's Field; while British and American sources differ on the result of the battle, Parker was one of the casualties. Leading his marines, he was hit in the thigh (as his grandfather had been at the Battle of Sullivan's Island), but unlike his grandfather, Parker died on the field of a severed femoral artery. According to midshipman Frederick Chamier, "“The whole animation of the party died when he drooped,” Chamier said in his account. “The Americans fortunately had begun another retreat; and our ceasing fire only led them to believe that we were following the quicker. Sir Peter’s only words were these: ‘I fear they have done for me … you had better retreat, for the boats are a long way off.” It took only about 10 minutes for Parker to bleed to death. 14 men under Parker's command died at Caulk's Field, 12 of which remain buried in unmarked graves at the site of the battle.