The lake is beginning to freeze again, and the bird population is adjusting for winter. Here is a part of large group of Greylag Geese on the Serpentine.

Many of these geese visit the park in winter, and sometimes there are more than 400. There is plenty of grass for them, even if they have to scrabble through the snow for it, and there is always some clear water even when the lake is frozen. It never freezes between the Serpentine island and the shore, or at the very top of the Long Water where the relatively warm water from the borehole feeds the lake. When the Serpentine freezes, the people from Bluebird Boats send out a motor boat to break channels in the ice.

Although Greylag Geese are a native British species, almost all the Greylags in England are descended from reintroduced birds. In the 19th century shooting reduced the population so catastrophically that the only the Scottish population is original.

More Shovellers have arrived on the Long Water and are beginning to form their usual circling groups. As a change from the usual gaudy adult males, here are a female, on the left, and two immature males who will not get their full finery until their next moult.

The Little Grebes have found that their current haunt on the Long Water is already partly frozen, and have been to fish at the Serpentine island. Here they are heading back before sunset; these small birds would not spend the night in the open. One of them is just beginning to dive: it flings its head down into the water and gives a hard kick with its powerful feet.

In very hard weather the Little Grebes congregate under the willow tree near the Italian Garden, which provides cover. There seems to be a good supply of small invertebrates for them to pick off the stems of water plants.

A Great Black-Backed Gull visited the Serpentine, where I saw it waiting for the pigeon-eating Lesser Black-Backs to leave their meal so that it could grab it. Here it towers over one of them, although a Lesser Black-Back is itself quite a large bird.

The smaller gulls guarded their prize carefully, and eventually the Great Black-Back gave up and flew away. It is perfectly capable of catching its own pigeons.