Black-headed gull and cormorant.
Better in large (go on, press "L").
First thing's first: I (tentatively) have good news! When I visited Eagle Pond this afternoon, the fettered fledgling was nowhere to be seen. I'm being optimistic, and assuming that this means that the rescuers yesterday managed to catch it, and it has now been taken to have its legs looked at, and to be cared for. That is what was being discussed over the weekend, so I am taking its absence to be good news! What a relief!
I had quite a good look around the pond to make sure that it really was gone, so unless it was burrowing (or the drizzle was really obliterating my observation skills), it has been rescued. Positive but also slightly sad...
To my blip picture: this is a black-headed gull in its rather perverse winter plumage (i.e. with a white head...). There were lots of them on the boating pond ("Long Pond") on Clapham Common, and some were drinking by dipping their beaks in the water on the wing. This one was coming down to drink! There was also a beautiful cormorant on the pond; it was air-drying its wings when I arrived (looking like a comedy gargoyle) but then took to the water briefly before flying away.
I found it hard to choose my blip: I got quite a few pictures of the gulls in action. The light was very poor, but I quite like how monochromatic my pictures have turned out despite being only cropped and curved (I adjusted the Tone Curve...). I've uploaded another one to BlipFolio (here): the gulls normally drink by lowering just their lower mandibles into the water, but this one went in a tad heavily, and ended up almost submerged.
*Update* I've talked to one of the rescuers, and it turns out that the man from The Swan Sanctuary caught the fledgling yesterday (on his fourth visit); it is now being looked after at The Swan Sanctuary and is doing well. It will stay there (in a barn initially) and will simply fly away from their lake when it is ready. I'll keep you up-to-date if I learn of any developments.