Early spring influx of adult Long-tailed Skuas Stercorarius longicaudus in northwestern Europe in March 2021

Abstract

The Long-tailed Skua Stercorarius longicaudus is a trans-equatorial migratory seabird that migrates between wintering areas off southern Africa and South-America to circumpolar, (sub) Arctic breeding grounds (Gilg et al. 2013; van Bemmelen et al. 2017). Long-tailed Skuas usually migrate far from land (Wynne-Edwards 1935; Pollock et al. 2000) and the species is therefore usually only seen in small numbers in northwestern Europe. In some autumns, influxes of exceptional numbers of Long-tailed Skuas occur along European coasts (van der Ham 1989; Dunn & Hirschfeld 1991; Vanloo 1996). Numbers seen during spring migration in Scotland fluctuate greatly depending on westerly and northwesterly winds, with up to three-figure daily counts in some springs (Wynn et al. 2014). However, influxes away from Scotland and in early spring have not been documented before. In March 2021, a small but remarkably early influx occurred in western Europe, with adult Long-tailed Skuas turning up in France, the United Kingdom and The Netherlands (but not in other northwestern European countries). Here, I describe the spatial and temporal pattern in these records.