Although we are not even into the New Year, the Lesser Black-Backed Gulls are beginning to get the pure white head of their summer plumage.

The Common Gulls, a closely related species but smaller, are also changing.

Black-Headed Gulls change the other way and get dark heads, actually deep brown rather than black.

The taxonomists, as busy as ever, have thrown them out of the genus Larus, to which Herring, Black-Backed and Common Gulls belong, and they are now lumbered with the dreadful generic name Chroicocephalus, which means 'leather-headed'. However, the Mediterranean Gull, which also gets a dark head in summer, remains within Larus.

Update: Have just heard the sad news that the Mediterranean Gull has been kicked out of Larus and put into a new and idiotically named genus, Ichthyaetus, which means 'fish eagle'. See comments below.

A young Herring Gull came ashore with a large stone overgrown with algae, which it had got by diving headlong into the lake and pulling up from the bottom. These green stones are absolutely the gulls' favourite toy, perhaps because they are quite difficult to get, and they are dotted all along the south shore of the Serpentine.

The number one buoy on the Round Pond is also a favourite of Herring Gulls. The number doesn't refer to its prime position, of course -- it's one of the buoys used as markers for model yacht races.

Pairs of Black-Headed Gulls perform this bonding display all year round, not just in the breeding season. The same display, done at a greater distance, is used to assert dominance over rivals.

The Round Pond was remade a few years ago with a horizontal underwater ledge all round the edge, to stop people from sliding down when they fell in. Most of it is too deep for Starlings to bathe, but luckily it was unevenly laid and there are a few shallow spots where they can enjoy one of their splashy communal baths. Another consequence of the work is that there is nowhere comfortable for Mallards to stand, and their numbers on the pond have greatly declined.

Another consequence of the modern obsession with health and safety has had better results. When a tree falls into the Long Water it can't be removed, because the regulations require a floating crane which is impossibly expensive. So the trees are let, and provide convenient spots for birds to perch and preen.

The blond male Egyptian Goose was trying to preen on the edge of the Serpentine, but the wing blew his feathers the wrong way. He has pale flight feathers, almost as light as those of Blondie. Being male, he has to inherit the sex-lined blond gene from both parents. Females don't need two genes to have pale heads, but the ultra-pale Blondie must have two copies.

A Goldcrest appeared in the yew tree next to the Henry Moore statue. Luckily for them, the recent cold spell was not too severe. They are numerous at the moment because of several successive mild winters.

The mild day encouraged a Great Tit to sing inside a bush near the bridge.

A Blue Tit perched on a neighbouring branch was silent, but I have heard them singing on recent mornings.

No owls again today, but at least the reliable white-faced Blackbird arrived for her daily treat of sultanas.