Gulls at the Eirol landfill, Aveiro (Portugal): March 11, 2014

On March 11 Pedro Moreira and I visited the Eirol landfill again. We searched for rings between 7:00 and around 14:30. The weather was great, no or hardly any clouds and a lot of sun, probably a bit too much for the time of the year. There were fewer gulls present; about 9.000 Lesser Black-backed Gulls, 1500 Black-headed Gulls, 40 Yellow-legged Gulls and two Mediterranean Gulls. Highlight of the day was a first observation of a Common Gull for the site. We managed to read the rings of 35 Lesser black-backed Gulls and 2 Black-headed Gulls.

 Common Gull Larus canus

Procambarus clarkii is a freshwater crayfish species, native to the Southeastern United States, but found also on other continents, where it is often an invasive species. In this area these tasty snacks are taken by White Storks and Lesser Black-backed Gulls in marshy areas. They can currently be found around the landfill in large numbers in the shape of regurgitations that were dropped there primarily by the gulls, I suspect. The number of storks is currently very low; we counted only one during this stay, though it might be possible that more storks visit the site at later times of the day. On the other hand, the recent floodings in the area might be very beneficial for the storks (as well as for Procambarus clarkii?) so there maybe is no need for them to come to the landfill. I hope that the people involved in this study: http://www.bto.org/science/migration/tracking-studies/stork-tracking/about are aware of relatively recent and increasing occurrence of Procambarus clarkii in the White Stork’s wintering areas.

Lost racing pigeon Columba livia forma domestica, with a ring we did not manage to read.

 Two photos of the first recorded Water pipit Anthus spinoletta for the Eirol landfill (thanks to Pedro).