All the Tawny Owls were visible today. Here are their positions in Google Maps -- enter the coordinates in the box where you would normally put a place name.
Tawny owlets and mother: 51.50537,-0.178313
Tawny Owl father: 51.507865,-0.179387
Tawny Owls' nest tree 51.507991,-0.17994
URL for Google street view of nest tree: http://g.co/maps/kst69

The male Little Owl was also in his usual daytime tree, and his mate out of sight, presumably inside the nest tree:
Little Owls' nest tree: 51.507613,-0.175765
Little Owl male's daytime tree: 51.507497,-0.176016
URL for Google street view of nest tree (sweet chestnut, right of picture) and male's daytime tree (tall lime, left of picture): http://g.co/maps/a6bsf

It was a slightly chilly, breezy day and I didn't meet anyone. I went round the lake. The Mute Swans are now nesting seriously, with a lot of territorial threat displays on the Serpentine. There are four nests that look permanent: on the east side of the Long Water, a bit to the north if you look across the lake from Peter Pan; on the east side of the Long Water near the bridge; on the Serpentine south of the outflow; and on the south side of the Serpentine just to the west of the Lido restaurant. The last of these had, I think, five eggs in it on Monday 2 April. I thought then that it was too exposed to last, but it is still occupied.

A Great Crested Grebes' nest is now a going concern at the east end of the Sepentine island.

This is not a very successful spot, as the Grey Herons can wade to it, and have destroyed nests in earlier years -- and of course, they are now themselves nesting on the island.

There are several black Mallards with white fronts on the lake; I think there are three altogether, all with slightly different markings. Other ducks include at least three Red Crested Pochards, and a pair of Gadwall.

There are quite a few Greenfinches singing on both sides of the bridge.