First Aberrant Coloured <i>Calonectris</i> Shearwater recorded in Madeira, Portugal

Herein, we report a Calonectris sp. shearwater with aberrant plumage, observed southwest off Madeira Island. The bird had an unusual amount of white feathering, more than has been reported so far for the genus. Both upperparts and underparts were predominantly white. Initially, we thought the bird was a leucistic Cory’s Shearwater C. borealis, but some characteristics could not be ascertained. Records of such aberrations should be published to provide a more comprehensive understanding of the subject.