First record of Scopoli’s Shearwater Calonectris diomedea in Slovenia

Abstract

Scopoli's Shearwater Calonectris diomedea breeds in the Mediterranean (BirdLife International 2016a), with isolated cases of breeding recorded on the French Atlantic coast (Mays et al. 2006). Following a recent reassessment at its largest colony (Zembra Island, Tunisia), the global population is estimated at 141,000–223,000 breeding pairs (Defos du Rau et al. 2015, BirdLife International 2016a). Based on limited data, the population appears to be in slight decline, 2% over three generations, but is still evaluated as “Least Concern” (Carboneras et al. 2013, BirdLife International 2016a). The majority of the population leaves the Mediterranean to winter in the Atlantic Ocean, mainly in three areas: the Benguela and Agulhas Currents, the Brazilian Current and the Canary Current (Ristow et al. 2000, Camphuysen & van der Meer 2001, González-Solís et al. 2007, Péron et al. 2012). The autumn passage to the Atlantic takes place between mid-October and late-November, spring passage in the reverse direction between late February and early April (Ramos et al. 2009). Until recently Scopoli's Shearwater, first described by Joannes Antonius Scopoli in 1769, was considered the nominotypical subspecies of the polytypic Cory's Shearwater, together with Calonectris (diomedea) borealis which breeds mainly in the Atlantic Ocean. Field characters to differentiate the two subspecies were described by Gutiérrez (1998) and the split first proposed by Sangster et al. (1999) based on differences in molecular data, morphology and vocalization. The decision was not universally accepted at the time, but is now more widely adopted (Sangster et al. 2012, BirdLife International 2016a). Because Scopoli was based in Carniola for a significant part of his professional life, his species descriptions are of particular interest for Slovenian ornithologists. The species is named Procellaria diomedea (Scopoli 1769) and Scopoli refers to Linnaeus's “Diomedea (exulans)” (Linnaeus 1766) and Jonston's “Diomedea” (Jonstonus 1650). He proceeds to briefly describe the species without giving