african balearica-pavonina banded beak bird black black-crested-crane black-crowned-crane black-head-patch captive crane crest crown display displayed displaying distinctive feathers forager golden-head-feathers gruidae gruiformes large long-legged long-necked omnivore omnivorous plumage spreading Sub-Saharan toes trained trees-roosting Ugandan-national-bird vertebrate white wildlife wings wingspan