The black stork (Ciconia nigra) is a large but fairly secretive bird. The black head, upperparts, wings, tail and long neck have a conspicuous green or purple gloss, contrasting with the white belly, undertail and ‘armpits’. The long legs and long, straight beak are bright scarlet in adults, especially during the breeding season, and a patch of scarlet skin also surrounds the eye. The male and female black stork are similar in appearance, though the male may be slightly larger, while the juvenile has slightly browner, duller, less glossy plumage, and a pale olive-green beak and legs. The black stork uses a range of calls, including a loud, ‘whinnying’ call at the nest, hoarse gasping, and beak-clapping.