Morphological Evidence for a Nail-Like Structure on the Wing Digit of the White Stork (Ciconia ciconia)

Abstract

Keratinized nail structures are typically restricted to the pedal digits of adult birds. During the anatomical examination of an adult white stork (Ciconia ciconia), a keratinized nail-like structure was identified at the distal end of the third manual digit. Gross morphological comparison with the toenail of the domestic chicken (Gallus gallus domesticus) revealed marked similarities in shape, curvature, and keratinization, supporting its identification as a true nail. To our knowledge, this is the first report of such a structure in C. ciconia, providing new anatomical evidence and a basis for future comparative and evolutionary studies.