Two of the four young Great Crested Grebes from the nest by the bridge were practising the courtship dance they will perform in earnest when they grow up. They did the head-shaking routine ...

... and even had a try at the bit where they wave vegetation at each other.

This dance does not have to be learnt, despite its complexity: it is instinctive. On the other side of the Atlantic, the big Aechmophorus species -- Clark's and Western Grebes -- have a similar dance. But it does have to be practised with a partner to get it right, and sometimes you see inexperienced young adults making mistakes and losing the careful synchronisation that is an important part of the ritual.

A pair of Pied Wagtails bred in Kensington Palace this year, lending the place a bit of class. So both species of wagtail managed to breed; the Grey Wagtails nested under the plank bridge across the waterfall in the Dell and fledged one young bird. Thanks to Roy Sanderson for this information.

On the edge of the Serpentine a Greylag Goose was paying attention to its tail feathers. Thy have to last a whole year and must be carefully maintained.

And on the Long Water, a Grey Heron was standing on a bit of netting and poking its beak through the mesh. There must have been some small invertebrates under the net.

Herons will eat almost anything, large or small. My park friend Roy (not the same Roy as above) once brought in a whole pound of cooked sausages and fed them to a heron. It ate the lot, without pausing.