Sierra leone. Grebo people. Carved bird mask ornate with quills, plaque and spike. Very rare. 40x18x16 cm (15,6x7x6,2 inch) 813 gr. (28,5 oz). GUEYE MUSTAPHA COLLECTION. The name Grebo (or Glebo) is used to refer to an ethnic group or subgroup within the larger Kru group of West Africa, to certain of its constituent elements, or to the Grebo language. Within Liberia members of this group are found primarily in Maryland County and Grand Kru County in the southeastern portion of the country, but also in River Gee County and Sinoe County. The CÃ´te d'Ivoire Grebo population Krumen is found the southwestern corner of that country.