The young bird with the Mute Swan on the little island in the Long Water, which I photographed yesterday, looked too yellow to be a cygnet. There was a clearer view of it today, and it is certainly a Canada gosling. It believes that the swan is its mother, because newly hatched geese 'imprint' on the first thing they see. And the swan seems to tolerate it.

She is still sitting on her own eggs, and presumably this little bird will grow up with the cygnets when they emerge. I can only suppose that the female of the Canada Goose couple that were at this end of the lake, and which for some reason never managed to settle in a nest, laid this egg in the swan's nest while the swan was away. I have never seen this happen before.

The Black Swan was back with his girlfriend after several solitary days. They were cruising about together contentedly as if nothing had happened, and he was calling to her.

The Canada Goose couple's one gosling hadn't been seen for a while, and there were fears for its life. However, it turned up today at the east end of the Serpentine, where its parents were keeping it well hidden in a patch of weeds.

Two Red-Crested Pochards visited the ponds in the Italian Garden, not a place where they have been before. There is a heavy growth of algae here after a few warm days, and they were diving among it. Red-Crested Pochards are vegetarian ducks, and evidently they were finding something they liked here.

Two Great Crested Grebes were having a fight on the Serpentine. It was not the usual wrestling match. One had clearly already won, and seized the other bird by the scruff of the neck and dragged it out of its territory.

Both dived after this and came up a hundred yards away after what was evidently an underwater chase. Grebes can move extremely fast when chasing under water; if you see this happening you have to run quite hard to keep up with them.

A Magpie was bathing in the Serpentine near the Diana fountain, and came out soaking wet to shake itself dry.

In the same reed bed, last year's young Grey Wagtail was working its way along the shore of the lake. It perched on a wire.

A Pied Wagtail whipped round to pounce on some tiny creature on the edge of the Round Pond.

There was a family of Long-Tailed Tits in a copper beech tree next to Lancaster Gate (which is 200 yards up the hill from Lancaster Gate tube station). This is one of the young ones.

A Wood Pigeon was eating pink hawthorn blossom near the leaf yard.

The male Little Owl was in his chestnut tree. It's getting quite hard to see him among the growing leaves.

A pair of Brimstone butterflies were flirting in the Sunken Garden. This is the male.