First Record of an ‘Ino’ Colour Aberration in the European Pied Flycatcher Ficedula hypoleuca

‘Ino’ colouration is a remarkably rare plumage colour aberration characterized by a significant qualitative reduction in melanin and reddish eyes. Here we describe the first report of ino colouration in a wild passerine bird species, the European Pied Flycatcher Ficedula hypoleuca. We found a nestling with an ino colouration aberration distinguishable from its siblings by its red eyes and the absence of pigmented feathers on the forelimbs at hatching. At the fledging age, the ino individual presented with reddish eyes and pale brown feathers and bill. All the chicks successfully fledged at the end of the nestling period. The most plausible hypothesis that explains this finding is a genetic mutation that affects the deposition of melanin pigments in feathers.