Grebes have very short and scanty tail feathers, which makes it easier for chicks to climb up. I think they must use their large trailing feet as control surfaces when they are flying.
One of the eldest chicks at the Serpentine island, in the shadow of the trees, was preening its shining white underside.
The brilliance of its feathers makes it less visible from below, an advantage for a bird that hunts fish.
Two Grey Herons were chasing each other around the Italian Garden. They momentarily perched in a tree, still defying each other. But the branches were very thin and they had to flap furiously to stay on.
Just after I took this picture, one of them lost its footing, lurched into the air and flew away, leaving the other triumphant but precarious. Where there are two herons, there is usually a quarrel. But I have never seen them actually fighting: their beaks are too dangerous to be used in anger.
Beside the Serpentine, some Black-Headed Gulls and Feral Pigeons and a juvenile Lesser Black-Backed Gull were squabbling over the end of a baguette. Needless to say, the big gull won the prize and flew away with it.
This Mallard in the Italian Garden evidently felt that the rain was not wet enough, so it stood under the fountain.
I didn't hear the Hobbies today. Perhaps they are heading for Africa.