As the rain fell, a couple of Carrion Crows were passing the time by annoying a Cormorant perched on the fallen horse chestnut tree in the Long Water.

Until ornithology became more scientific, it was believed that the Cormorant was a seagoing member of the crow family. Its common name comes from the Latin corvus marinus, 'marine raven', and its taxonomic name is Phalacrocorax carbo, 'bald raven, coal-black', a remarkably inaccurate description.

A Grey Heron stared fiercely at the camera with its yellow eyes, possibly wondering whether it was edible.

The bulging eyes are set far enough forward in its skull to give good binocular vision down to the tip of its beak, essential for accurate strikes on fish. Presumably they have to learn to compensate for the refraction of the water and hit lower down than the fish appears to their eyes; if they went for what they saw they would strike too high and miss it.

All ten Great Crested Grebe chicks were in good order, and all noisily pestering their parents for food, but they were too far away for a good picture. So here is an adult who was preening close to the edge, and had a flap to settle her newly replaced flight feathers.

Great Crested Grebes' wings are quite long but very narrow, and therefore heavily loaded in flight. They have to travel fast and flap rapidly to stay up, and their unstick speed is very high, which is why takeoff is such a frantic affair involving a 50-yard run.

I think this Herring Gull standing on the old water level gauge in the Serpntine is one year and a few months old. The first trace of adult grey feathers is beginning to appear on its back, and fairly soon it will be clearly recognisable as a Herring Gull rather than a Lesser Black-Backed Gull. I know it is the former, because after I had taken the picture it flew away, revealing the distinctive whitish inner primaries of the species.

Here is another mystery mushroom, which I saw on Buck Hill. It was about 7 inches tall with a very slender stem and small cap. It is clearly past its best, with black sticky gills and the edge of the cap beginning to decay. I don't think I have ever seen this species before in the park. It has been a very prolific mushroom season.