A sunny day, and the ice on the lake is melting noticeably -- though we are not out of the freezing weather yet. With the pressure off, there was no remarkable water birds on the lake. Even the familiar Red-Crested Pochards seem to have flown away to join the mob in Regent's Park, which was counted at 74 two days ago.

However, the Bearded Tits were still in the reed bed.

You can tell that they are present from hundreds of yards away, by looking at people coming away from the spot with binoculars and big grins on their faces.

While we were looking at the Bearded Tits, a Song Thrush flew down and perched on the lakeside railings, and looked at us curiously for a minute before flying away across the lake.

Railing are actually a help for the peculiar activity of park birdwatching. They keep people at a respectful distance from the Bearded Tits, just close enough to photograph them but not so close as to scare them away. I was talking to someone about the fact that the birds had been here unobserved since 11 December -- they were seen but the report didn't get through -- and he said that it was a stroke of luck, because it allowed them to get used to the passing crowds, so that when people turned up later to stare at them and point huge lenses in their direction, they were not frightened.

Birds understand that humans stay on the other side of the railings, and will therefore approach you quite closely, reassured by the barrier. Here a Blackbird roots around in the melting snow a few feet from me, unworried by my interest in her.

Birds are long-sighted and can't see objects close to them clearly. But many of them, including Blackbirds, have sensory bristle feathers like whiskers at the sides of their beak which work in exactly the same way as cats' whiskers, helping them to detect objects such as worms.

You can see the whiskers more clearly in this close-up of a Robin.

There was a small flock of Siskins in a tree on Buck Hill, but they were too high up for any attempt at a photograph.