Abstract

This article presents sightings of 25 Scopoli’s Shearwaters Calonectris diomedea photographed in Scillonian waters between 28th July and 15th October 2023. Prior to this, the status of Scopoli’s Shearwater in Britain was as a very rare vagrant, with just three records accepted by BBRC, two of which came from Scillonian waters. In this paper, the 2023 influx is placed in the wider context of a significant increase in seabirds during autumn off the Isles of Scilly since 2017 and a changing marine environment in the Northeast Atlantic, including waters off southwest Britain. The article also details the criteria employed to separate the 25 Scopoli’s Shearwaters from the species’ cryptic – and commoner – counterpart, the Cory’s Shearwater C. borealis. A sample of 16 birds seen during autumn 2023 is used as a representation of the sightings, with their identification examined using photographs and captions; this illustrated discussion advances knowledge surrounding the identification of out-of-range Scopoli’s Shearwaters. Finally, the article argues that, in favourable circumstances, safe identification of Scopoli’s Shearwater is possible without photographic documentation.