The dominant Mute Swan family on the Long Water are amazingly alert to any invasion of their territory. They were touting for food at the Peter Pan statue when an interloper swan appeared under the bridge 200 yards away. Within seconds both parents were off to war, with their teenager trailing off behind.

And aq few second later it was a full-scale charge. The invader hastily retreated under the bridge, which marks the frontier. (Sorry about the quality of this photograph, taken against the light.)

Buck Hill was covered in Wood Pigeons poking around in the grass, at least 50 of them. I don't know what they were eating in the newly mown grass. They are vegetarian, at least in theory, so they would not be looking for the insects which attract Carrion Crows and Magpies to the same spot. Maybe it was grass seeds scattered by the mowing.

One of them had met with a misfortune.

This might have been the work of a Sparrowhawk: the females, larger than the males, are certainly capable of killing a Wood Pigeon. But I am not sure that one could lift this large bird. It had certainly been carried off, as there was no trace of anything but pale grey feathers. The killer might have been a Peregrine.

The area to the west of the Albert Memorial, where the grass had been ruined by two exhibition marquees in close succession, has been rotavated and reseeded. With five minutes of the sower starting his work, all the Feral Pigeons in the locality had descended to eat the seeds. A proportion of seeds do survive and sprout, but the loss must be very high.

The eldest Great Crested Grebe chicks on the Serpentine, now 10 or 11 weeks old, have begun to grow proper black crests on top of their still stripy heads.

They will not be able to fly until they are about 14 weeks old, by which time their stripes will have largely disappeared and they have something like their parents' plain winter plumage, only a faint trace of black line beside the eye showing that they are this year's birds.

This picture also shows what a fine camouflage the stripes are against the ripples on the water.