U.S. Army Lt. Col. Mark Vaughn, Combined Joint Task Force - Horn of Africa deputy director of civil military operations, clears low branches of a prosopis tree to make room for the expansion of the lion enclosure at the Discover and Aid Nature Animal Refuge in Djibouti, Djibouti, Feb. 19. U.S. service members deployed to Camp Lemonnier, Djibouti, routinely volunteer at the refuge during their spare time.