Thursday, February 21, 2013

Eirol landfill, February 19, 2013: the last of this winter's visits, and the terror birds are back!



This entry is about my most recent visit to the Eirol landfill (February 19), during which I was hoping to gain a good final number of color-ring sightings, as it would be my last visit to the site for this winter. There were still plenty of gulls present (about 16.000 Lesser Black-backed gulls Larus fuscus), but as mentioned before the ring-reading conditions there are not as good as they once were at Taboeira: rings get dirty more easily, birds are harder to observe from the right angles, and many of their roost sites are out of sight for me.
This time things were a bit different, primarily because the first Black Kites Milvus migrans have returned from their wintering quarters in Africa. These kites continuously flushed the gulls from their hidden roost sites, forcing them to perch at different locations, allowing me to see their rings more easily. A total of 58 color-rings were read and these had been applied on Lesser Black-backed Gulls in Britain (excl. Guernsey) (19), Guernsey (18), The Netherlands (10), Norway (3), Germany (2), France (2), Denmark (2) and Belgium (2).
British birds seemed to be dominating the site. I noticed a similar situation taking place a year ago at Taboeira, when during the second half of February the number of British gulls appeared to increase while those originating from other NW European countries decreased. This will undoubtedly have something to do with the gulls’ spring migration movements, as the majority of the birds will already be on their way to their breeding grounds further to the north. I will be following some of them in a few weeks from now.

 
The first of three Black Kites that showed up during the day…


…and the mass-hysteria among the gulls that always seems to follow the appearance of a kite.


These kites were more than capable of expelling the gulls from the large mound of sand that is located at the east side of the landfill. They’re more than welcome to do so, as this allowed me to observe a lot more gulls in places where their rings could actually be read...

I.e. on the roads right next to the observer.


And this time the birds roosting in the pit were too afraid to kneel down, so there were plenty of legs to scope out.


Then of course it’s important that the ring itself allows proper reading and its inscription is not either too worn or too dirty. I'm not sure where this one came from, but it's probably British.

A new one for me; Chris Perrins’ GREEN TA, with a tiny and dirty WHITE inscription (vertical inscription; top – bottom). Also very British.


Philippe Dubois’ RED 974K with a WHITE inscription, from France. Well, initially there was a white inscription visible on this ring; nowadays you'll have to get very close to this bird for a proper reading.


RED TB5.T, BLACK inscription, a bird from Paul Roper & the North Thames Gull Group, is showing an unmarked companion how to drink dewdrops in the early morning.


 David Sowter’s BLACK WC3W, YELLOW inscription; very condensed inscription, but in the end Britannia ruled the waves at the landfill.


Apart from color-ring reading I spent some time inspecting gull carcasses again. Unfortunately for Mike Marsh the only bird from him that got reported from Eirol was this LBBG RED AZ.AC, WHITE inscription (metal BTO GR20352). It was ringed as a pullus on the 4th of July 2010, on Havergate Island, Orford, Suffolk. Afterwards it got reported regularly by others in Faro (Portugal), once from Torreira, and a few times by me from the former Taboeira landfill. An additional two British ‘metal only’ LBBG’s were found. A broken wing had been the initial cause of death for all of these three gulls.


Besides the resightings, the overall birding turned out to be very good again. It all started off with an adult male Marsh Harrier Circus aeruginosus patrolling the site for a while. It caused some disturbance among the gulls, but nowhere near as much as the first kite that would show up an hour later.

A single Mediterranean Gull Ichthyaetus melanocephalus among Black-headed Gulls Chroicocephalus ridibundus and one Lesser Black-backed Gull.


A Pied Wagtail Motacilla alba yarrellii, which I consider to be part of the British invasion of the landfill as well.



I also ran into this strange looking bird, presumably a female Herring Gull Larus argentatus. Considering the number of gulls I see on a regular basis, the number of rarities that get reported by me (compared to those reported by my ‘gull friends’ from the Iberian Peninsula) seems to be rather low. I suspect that I spent too much time scoping out gull legs instead of gulls themselves, so I probably miss out on a lot of fun. Still, Herring Gulls are rare in this part of the world, but in a few weeks from now I’ll have plenty of them flying around my head and they will appear normal again.