During recent visits to the landfill we were pleased to see the immature Peregrine Falcon Falco peregrinus (or hybrid?) was still around, putting some pressure on the Black-headed Gull Chroicocephalus ridibundus population. Recently, many new gulls have arrived from the north. The number of Black-headed Gulls increased to about 500 birds. Many of the new birds will have been unaware of the falcon’s presence. This will make them easy prey for the Peregrine, which is still operating from the top of the same Eucalyptus tree, aiming for the gulls that come to take a bath in the ditch below the tree. The ground around this ditch is currently littered with the remains of at least 9 Black-headed Gulls.
Among the new gulls that recently arrived at the site was this Black-headed Gull from Poland (White THPP).
The single Common Gull Larus canus were recorded on December 3, 2014.
It would be interesting to see how the Black-headed Gulls will deal with the presence of the falcon this winter. Since I’ve never visited Eirol in December there’s no data available about the number of gulls present at the site around this time. At the time the Taboeira landfill was still operational, during four visits in December 2011, I counted between 2500 and 5000 Black-headed Gulls...
