This Treecreeper was photographed from directly underneath as it was walking along the underside of a branch, hanging on with its long hooked claws.
It is perfectly camouflaged. When it feels threatened, a Treecreeper often freezes. Staying perfectly still makes it invisible.
Brown speckled plumage is also very effective camouflage for birds that forage in leaf litter, like this Wren in the scrub near the Rima relief.
I had gone to Rima to listen for the Lesser Spotted Woodpecker, without success. There have been several reports of this species around London in the past few days. Perhaps a band of them is passing through on its way to wherever Lesser Spotted Woodpeckers go.
The Cetti's Warbler was still singing occasionally in the brambles on the west side of the Long Water.
The Scaup was also still on the Serpentine, inconveniently positioned halfway along the reed bed in front of the Diana fountain and very close in to the edge, to the frustration of several people who had come to photograph it.
A pair of Egyptian Geese spent several days recently apparently nesting on one of the floating rafts of reeds at the east end of the Serpentine. Then they abandoned the place. Now they are back on another raft. Usually Egyptians nest in tree holes, and it is not at all clear what they are doing.
A pair of Canada Geese were charging around near the Serpentine island, driving away rivals.
The white Mallard was right next to them. Unperturbed, it went on eating algae.
A Pochard was preening near Peter Pan, and finished the job with a vigorous flap to settle its wing feathers in their proper positions.
One of the Little Owls in the chestnut tree came out on a branch several times for a few minutes, but unfortunately not while I was there. The weekend crowds disturb them. But the male Tawny Owl was in his usual place, enjoying the warm sunshine.