Agreement on the Conservation of Albatrosses and Petrels

Bill deformity in Scopoli’s Shearwater

Vittoria Roatti (Ornis Italica, Rome, Italy) and colleagues have published on bill malformation in chicks of Scopoli’s Shearwater Calonectris diomedea in the open-access journal Marine Ornithology.

The paper’s abstract follows;

“We report three cases of bill malformation in Scopoli’s Shearwater Calonectris diomedea on Linosa Island (Sicily, Italy) that were found during monitoring of the colony over a 13-year period.  The cases were observed in pre-fledging chicks; two of the birds were also in poorer body condition compared with chicks of the same age. No adults in the colony have been found with similar bill malformations despite a much larger sample of recorded adults.  We suggest that the observed malformations impair survival and that the chicks we encountered would likely starve after fledging.  The frequency of bill malformation found on Linosa is less than one percent, which is consistent with cases reported in the literature for other species.”


Scopoli’s Shearwater chick with bill malformation: side view (left) and top view (right), from the publication


Roatti, V., Massa, B. & Dell’Omo, G. 2019.  Bill malformation in Scopoli’s Shearwater Calonectris diomedea chicks. Marine Ornithology 47: 181-184.

John Cooper, ACAP Information Officer, 17 August 2019