During this time, Vandegrift continued to direct efforts to strengthen and improve the defenses of the Lunga perimeter. Between 21 August and 3 September, he relocated three Marine battalions, including the 1st Raider Battalion, under Merritt A. Edson (Edson's Raiders), and the 1st Parachute Battalion from Tulagi and Gavutu to Guadalcanal. These units added about 1,500 troops to Vandegrift's original 11,000 men defending Henderson Field. The 1st Parachute Battalion, which had suffered heavy casualties in the Battle of Tulagi and Gavutu–Tanambogo in August, was placed under Edson's command.