A pair of Great Crested Grebes were building up the nest at the corner of the reed raft at the east end of the Serpentine. At first this seemed like a pleasant if unremarkable picture ...

... but then another pair of grebes came up and chased them off.

These must have been the original owners of the nest, which had been stolen by the other pair.

Two young Herring Gulls were hunting for worms in the Diana fountain enclosure, and one of them has now learnt the worm dance to perfection, and pulled up three worms inside a minute.

The other was not dancing so well and was bringing up fewer worms, but it will learn. However, there was also a Common Gull which had apparently copied the worm dance from the Herring Gulls, as I've never seen one doing this before. It had the pattering technique absolutely right ...

... but only caught one worm in the five minutes I watched it, perhaps because, being a lighter bird, it wasn't causing enough vibration.

The Egyptian Geese at the Lido have lost one chick and are down to five.

The pair on the Round Pond now have none. But before you get too upset about this, remember that the number of Egyptians in the park has increased from two twelve years ago to over 100 now.

In 1202 Leonardo of Pisa, usually known as Fibonacci, worked out how fast a pair of rabbits would multiply if all survived. He reckoned that rabbits reach breeding age in one month, and supposed that each fertile pair would produce two young. After 12 months there would be 233 pairs, or 466 rabbits. Our Egyptians reach breeding age in two years -- but suppose they had six in every brood and bred twice a year. I leave it to better mathematicians than me to work out how many there would be if they all survived.

The Black Swan was still with girlfriend number one today.

The girlfriends are getting harder to recognise as they turn white. Girlfriend one still has a larger patch of white on her left wing, though the difference is evening out. She also still has quite a dark top to her head, contrasting with white on the nape of her neck.

Here is girlfriend two, alone today and being fed by Jorgen. She is whiter than number one, and her most noticeable feature from a distance is two faint pale rings round her neck.

You will also notice a difference if you feed them out of your hand. Number one will bite you, but number two is very gentle.

One of the Mute Swans has laid an egg on a raft at the east end of the Serpentine, and was turning it over. There is no evidence of a nest being built, so it's not clear what's going on.

There are two other eggs on the rafts. One belongs to a Greylag Goose, which was sitting on it the second time we passed. The other seems to have been abandoned.

The onset of the nesting season has made the Mute Swans much more aggressive, and there have been several serious fights in the last few days.

This young female was chased by the resident male on the Long Water, took off in the direction of the Italian Garden, and tried to make a tight turn to head back to the Serpentine. But she misjudged it, hit a willow tree with her wing, and crashed ignominiously through the branches into the brambles. Fortunately she was not hurt, and after sitting in the brambles for a quarter of an hour she stood up.

However, the dominant male was still in the water and wouldn't let her come down. Probably he will have relaxed and gone away and she will have been able to sneak out. But Malcolm the wildlife officer was keeping an eye on her, and if she remained trapped he would have bundled her up in his canvas swan straitjacket and taken her to the Round Pond, home of low-status swans.