The usually reliable male Tawny Owl was not visible this morning, to general consternation. Fortunately when I went back in the afternoon he had come out again in his usual place.

The adult Great Black-Backed Gull had returned, and was sitting far out in the middle of the Long Water, easy to miss among the Lesser Black-Backs until the two came near each other and you could see how huge it was.

Note the heavy bill and thick neck, and also the very dark colour of the back, darker than any of the Lesser Black-Backs (though these come in two colour morphs, Larus fuscus intermedius, which is mid grey, and L. f. graelsii, which is darker; the first type is commoner here). Less obvious in this shot is that the row of white spots on the folded wingtips are large; in the Lesser Black-Back these are quite small.

It was the day for the monthly bird census. The last time I counted, at the end of December, this bird also showed up on the lake to be included in the count.

A pair of Mute Swans was displaying behind the wire baskets around the Serpentine island, an oddly cramped space for these large birds.

At first I wondered whether they were planning to nest on the island. But, as you can see, they are both quite young and their bills have still not turned the adult orange colour. The swans' nest site on the island is the most prized of all the available places, since it is safe from foxes, and a low-ranking young bird would never be able to claim it. In fact I think they were displaying here to avoid being attacked by more senior birds.

A pair of Moorhens in the Italian Garden seemed to be looking for a nest site in one of the wire netting enclosures for water plants.

The mesh presents no obstacle to Moorhens, since these agile birds can climb it in an instant. By the time any future young Moorhens are too large to get through the mesh, they too will be able to climb over.

At the edge of the leaf yard, Charlie the Carrion Crow was having a face-off with a medium-sized rat.

They wisely decided to leave each other alone.

Overhead, an alert Jackdaw was waiting to pounce on any food offered to the crows. They are so much faster than the rather sedate crows that they often succeed.