A pair of Great Crested Grebes has been hanging around the west end of the Serpentine island for several days, and it looks as if they are going to build a nest behind the wall of floating baskets.

This spot has been tried before, unsuccessfully -- I think it was raided by Grey Herons which, from a grebe's point of view, are the main hazard of nesting on the island. But the Serpentine is so poor in suitable nest sites that there is little choice.

Meanwhile the grebes at the east end of the island have abandoned a nest that they built behind the baskets, but may be expected to go to an overhanging bush, a site that has been used before, sometimes successfully.

The idea of these floating baskets was that they would make a wall of water plants around the island, which would both purify the water and look pretty. It hasn't worked very well. Any plants that grow beyond the mesh are promptly chewed off by the waterfowl, and they have died down to a stunted remnant. Some new plants were put in the baskets in the autumn, and it remains to be seen if they will do any better. The horizontally laid twigs in the background of the picture are another water purification measure: according to the men who put them in, they are supposed to stimulate the growth of beneficial organisms (they didn't say which ones).

A Blackcap was singing on the fence at the back of the Lido. Annoyingly, it flew off as I raised my camera.

For some time the Mute Swans have been using the patch of water near the Serpentine outflow as a kind of marriage market, with displays between prospective partners and occasional outbreaks of aggression. Here a male has a rather violent bath right next to the group; I don't know whether this is a kind of display or whether he just felt like having a wash.

And, photographed straight down from the parapet, a young and low-ranking swan ignores the kerfuffle and looks for something to eat.

In the Dell, a Wren was poking around under a holly bush, dwarfed by the leaves.