Saturday, 7 May 2011


Baltic Gull (Larus fuscus fuscus). 04.06.06. Eggegrund, Gastrikland, Sweden (photo: P. Aspenberg). Bird ringed in Villanueva de la Serena on 22.02.06 por J. M. Traverso.

Some of our recent blog entries have dealt with species seen for the first time in Extremadura. Or rather the first known and conscious sightings of said species. On this occasion we are recording what we believe to be the first ever certain record in Extremadura of a particular subspecies of the otherwise common Lesser Black Backed Gull (Larus fuscus). The nominate subspecies of this gull is called the Baltic Gull (Larus fuscus fuscus). This race has a very dark, almost black back; field observations are never accepted, only of ringed birds in the hand. The photo of the Baltic Gull alongside was taken on 4 June 2006 on the Baltic coast of Sweden, in Eggegrund, Gõvle, Gastrikland (P. Aspenberg). What's so special about a Baltic Gull seen on the Baltic coast, where, as their name suggests, they're abundant. Well, the remarkable fact in this case is that the bird was ringed in Extremadura two years earlier, on 22 February 2004. At the time the bird was classed as an immature female; it was captured and marked with a white ring (code N548) on the landfill site of Villanueva de la Serena by Chema Traverso. The information published here would never have come to light without the collaboration of Javier Marchamalo, who passed on crucial data.

The Lesser Black Backed Gull is traditionally divided into three subspecies in Western Europe:
- graellsii: slate grey mantle, breeding in the British Isles and the centre and west of Europe; this is Extremadura's commonest wintering gull
- intermedius: darker mantle that phases into the other two races at both extremes; also turns up now and then in Extremadura; its range is the North Sea so it is intermediate not only in mantle colour but also in distribution
- fuscus: very dark mantle, breeding in the Baltic Sea and wintering in Africa, migrating through Eastern Europe; it is considered to be a rare vagrant on the Iberian Peninsula.

A few pundits choose to divide the bird into two species: Lesser Black Backed Gull (Larus graellsii, with two races, graellsi and intermedius) and Baltic Gull as a species in its own right (Larus fuscus).