Shovellers move in big circles because the wake of the bird in front brings up the small aquatic invertebrates and plants that they feed on, filtering them out of the water with their huge beaks. So they are rather like little flying whales.
A Blackcap was clicking in the bushes near Peter Pan, sounding like an irritated Robin but louder. It would not come into view for a picture, but while looking for it I found a Nuthatch in a dark corner, hanging upside down from a stem and probing insects out of a hole in a branch left by a twig snapping off.
This view of a Grey Heron is often the last last thing that a fish sees.
The herons on the Serpentine are now remarkably unafraid of people, and will wade in when the waterfowl are being fed, pecking ducks and pigeons out of the way with their terrible beaks.
All the young Great Crested Grebes were in good order, though the ones on the Serpentine had had to retreat to the east end because there was a triathlon going on. Here one of the three young chicks approaches its parent to take a fish.
You can see the strange markings on its face. When hatched, they have a bare red patch on the crown of their head, and two other red patches in front of their eyes. The eye patches soon disappear under a cover of little grey feathers, but the patch on the top takes longer to fill in. These patches stimulate the parents to feed the chicks: red is an exciting colour for grebes, as it is for many birds.
In case you thought that fish was too large for the chick to swallow, here it is going down.
Andy Sunters, who took the fine picture of a Hobby published in yesterday's blog post, tells me that on the day he took it, Tuesday, he briefly saw a large gull-like, dingy coloured bird flying past. Yesterday he was at the London Wetland Centre and saw what seemed to be the same bird again. He was told that it was an Arctic Skua on passage. So it's not a definite sighting here, but an interesting possibility.