More Shovellers have arrived: there were 12 on the Long Water and two at the Serpentine island. Inconveniently for them, the second frosty night of the cold spell has begun to freeze the lake, and they need a fairly large open area to shovel up their food. Here a small party cruises around in a hole in the ice.

The gulls are less bothered by ice, since they can scavenge food from anywhere. Here a Black-Headed Gull examines its reflection in a shallow pool of water on top of the ice sheet.

It is thought that birds don't recognise a reflection as being of themselves, and certainly the silly Egyptian Geese which used to threaten their reflections in Anish Kapoor's Sky Mirror didn't have a clue what they were seeing. But I think that urban Feral Pigeons landing on window sills, and seeing their own reflection apparently coming towards them on a collision course, must have understood about reflections by now.

There was a strange rainbow streak in a high cirrus cloud, 22° to the left of the sun, with its red side towards the sun.

It was a 'sun dog' or parhelion, caused by ice crystals in the cloud. If there had been more clouds with ice in them, there would have been a circular rainbow halo around the sun, but the brightest spot -- central in this picture -- is always level with the sun. In extreme conditions, the bright spot forms a brilliant 'mock sun' on either side of the real sun.

Only the male Tawny Owl was out today, in his usual place, sunbathing with his back to the sun to avoid irritation to his sensitive eyes.

His mate would probably have been inside the tree, but they will not actually be nesting yet. After the glorious liberation of having kicked out their last brood, the couple are just easing themselves back into the routine of parenthood.