The Lesser Black-backed Gull, Larus fuscus, in Piedmont and Aosta Valley: distribution, population trend, phenology and significant spring concentrations.

Piedmont and Aosta Valley (NW Italy) data on Larus fuscus were analyzed up to 2010. The species’ status is transient and irregular wintering in Piedmont, vagrant in Aosta Valley. The species was contacted in every months of the year, peaking in March. Since 2006 there has been a significant increase in observations (from an average of 3.84 data/year in 1980-2005 to 61.40 in the period 2006-2010), which affected especially Turin plain. During 2008-2011 spring significant concentrations were found at two lakes in Piedmont, one of which is used as a roost site. Spring concentrations of this magnitude are of national relevance and are comparable with those found in bordering areas of Switzerland and France in the same period of the year and like those have been linked with bad weather conditions. Is also shown a link between presence areas and the presence of landfills, used as feeding sites.