I went to see if the male Tawny Owl was visible, and he wasn't. But at the bottom of their nest tree, the hole which had a Starlings' nest in it last year now has a Ring-Necked Parakeet in it.

These birds had better watch out, because the tenant upstairs would like to eat them. The two plane trees beside the Serpentine, just west of the two small boathouses, always have one Starlings' nest in each of them, and two pairs of Starlings had already claimed them. But higher in the eastern tree, another Parakeet had also taken a hole.

It is all part of the unstoppable spread of these birds. But there are so many trees in the park, and so many holes, that there is really no pressure on space, and it is not as if Starlings, or Great Spotted or Green Woodpeckers, or Nuthatches or Treecreepers, are being forced out. There is, however, competition for what are seen as the best holes.

There was a Coot carrying a twig to a nest site under the willow tree near the Italian Garden, so they are getting ready too. And a Blue Tit was also alternately singing and exploring a hole on a tree just to the south of the Serpentine Gallery.

The tree is one of the park's exotic species, a Manna Ash, Fraxinus ormus, from southern Europe, and carries a label saying so. Will keep an eye on this place and see how the tits get on. But there is another spell of cold weather coming that may delay all these preparations.

On the Serpentine, I watched the two Great Crested Grebes who have a nest in the reed bed at the east end. They swan briskly up the lake and another grebe got submissively out of their way. This bird didn't have much of a crest, and I think she is their offspring from last year's nest -- certainly a female, as you can tell from her slim build. She came over to the north side of the lake and hunted for small fish along the shoreline.

I saw her catch one, but she swallowed it immediately under water.

Not in the park, but quite nearby in the Harrow Road, there were 15 Waxwings in a crab apple tree. These lovely birds seldom visit the park, though you would think there were fruiting bushes to attract them.