An abnormally coloured Calonectris shearwater is photographed off Madeira

Calonectris sp. shearwater with abnormal plumage, off Calheta, Madeira, Portugal, 14 November 2023, photograph by Pedro Nascimento (from the publication)

Pedro Nascimento (On Tales – Unipessoal, Limitada, Funchal, Portugal) and colleagues have published in the open-access journal Marine Ornithology on photographing a shearwater Calonectris sp. with abnormal plumage.

The paper’s abstract follows:

“Herein, we report a 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.”

Reference:

Nascimento, P., Santos, E., Gonçalves, J. & Teixeira, M. 2025.  First aberrant coloured Calonectris shearwater recorded in Madeira, Portugal.  Marine Ornithology 53: 115–117.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 19 March 2025