The sound of a Hobby calling brought people to a tall plane tree on the path leading north from Physical Energy.

All four of us thought we could intermittently hear and see two Hobbies, but it's hard to be sure when you are running around the trees chasing occasional calls and catching fleeting glimpses. Of course we hope that the original pair have both got back from Africa, and that they will be nesting in some unfindable place.

The new Mute Swans' nest on the little island in the Long Water now has at least one egg in it, as could be seen when the female swan went off for a bite to eat. She should have covered the nest with reeds before leaving -- the female of the original pair would never have been so careless.

However, all was well when she came back and clumsily scrambled and flapped her way back on. The sides of this artificial island are too steep and high for a swan's convenience, but they get on.

The first Black-Headed Gulls -- just five of them so far -- have returned to the Round Pond. They still have the chocolate-brown heads of their breeding plumage, which will change to white with a small dark spot over the ear. This one has found something nameless and gloopy to eat in the water.

The first Greylag Geese to moult are already regrowing their new wing feathers.

The slowest to moult have still not lost all their old feathers, and yesterday I saw two just managing to fly on gappy wings.

A packet of cornflakes poured on on the edge of the Serpentine proved surprisingly popular with various waterfowl. A Grey Heron flew in to see what was on offer, but didn't fancy them and flew away.

So far almost the only other food I have seen herons ignoring is peanuts in the shell. They haven't worked out how to open them, something that a clever Carrion Crow can do in a couple of seconds.

This crow was enjoying a bath in the Serpentine.

The pair of pigeon-eating Lesser Black-Backed Gulls had just had a meal, leaving the almost bare carcase for a lower-ranking gull.

So far the only gull I have seen successfully catching a pigeon is the male of this pair, though I have seen others try and fail. Clearly it requires both skill and strength: the male gull is unusually large.

The white Mallard takes a detached view of the mating raids of the drakes, and is not bothered by drakes either. I'm still unsure of the sex of this bird.