On one of the baskets at the Serpentine island a Cormorant was behaving strangely, picking up and dropping a feather.
I wondered whether Cormorants eat feathers, as grebes do to wrap up fishbones so that they don't injure their digestive tract. When I got home I checked, and it seems that they don't -- they regurgitate the bones instead. So it looks as if this bird was just playing with the feather.
Moments later, from the same spot, I saw the Great Crested Grebe on the rightmost of the three closely spaced nests also apparently playing. It was throwing this piece of paper around, not making any attempt to add it to its nest. Eventually the paper blew away.
Both these pictures are very dark because they were taken in the shade of the trees on the north side of the island on a dull day.
Offshore from Peter Pan, a Great Crested Grebe that had been preening its wings stood up and had a good flap to settle the feathers in place.
Otherwise there was nothing remarkable to see, though the close-up view of the family life of the Moorhens, Coots and Mallards on the Italian Gardens ponds is always worth a visit, and so is the spectacle of the young Great Tits chasing their parents through the bushes in the leaf yard.