The sight of a gull knocking another off its perch is a usual one. Senior gulls displace juniors, and big gulls displace smaller ones. So it was a surprise for a young Lesser Black-Backed Gull trying to push off a little Black-Headed Gull when the intended victim stood fast. The two collided and fell into the water, and there was a brief fight which, even more surprisingly, the smaller gull won, driving off its adversary. In this picture it looks as if the head of the Black-Headed Gull, farther from the camera, is as big as that of the Lesser Black-Back and it might be a Herring Gull, but this is just a trick of perspective: in another picture of the incident you can clearly see the black trailing edge of the Black-Headed Gull's wing.

The numerous Black-Headed Gulls were being a sore nuisance to the four families of Great Crested Grebes, and a lot of hasty diving by parents and young was necessary to get them all fed. Here one of the younger family on the Serpentine seems to be expressing its annoyance by flapping its half-grown wings at a gull.

This was not the only trouble for the grebes. The appearance of more fish from the wire baskets of twigs near the bridge had attracted Cormorants as well as Great Crested Grebes -- some of the fish are 3 inches long, enough to give a Cormorant a light snack. This grebe is skittering out of the way after a Cormorant passed close underneath it.

And here, beside the island, is another Cormorant in an oddly drooping posture. It seemed to be drying its wings but couldn't be bothered to stand up and hold them out in the usual way.

I wondered whether it was feeling unwell, but a few seconds later it lurched gracelessly off the post and started fishing with its usual vigour.

The male Little Owl was in his usual place, dozing in the sunshine.

However, the noise of us talking under his tree woke him up and earned us a censorious stare.