The two families of Great Crested Grebes on the island were having one of their territorial disputes, which have been exacerbated by both of them being pushed round to the shore side of the island by the Olympic disturbance. The frontier of their territories is in front of the left tree trunk in this picture, and opposing birds are lined up at the edges.

They go into their low threat posture facing each other. If it seems advantageous, they can rush forward in this position, beaks at water level, trying to ram each other like little galleys. A opponent faced with a sharp beak approaching at speed has no choice but to get out of the way.

This time, however, they contented themselves with threatening gestures and calls, and honour was satisfied and they could exchange endearments with their mates to celebrate their exploits. The invisible frontier remained in exactly the same place.

Farther out on the Serpentine, three adult grebes were fishing peacefully side by side, a sign that they had only just flown in. They abandon their territorial behaviour to fly, which they do by night, and then take it up again shortly after arrival.

In contrast, a large flock of Starlings were pusuing their communal life inside a large holly tree on the west side of the Long Water. They constantly flock to this tree, whether or not the berries are ripe and edible, simply because it is one of their accustomed meeting places. You hear their loud twittering and whistling and clicking and wheezing coming out of the dense foliage, but often they are all hidden and it seems that the tree itself is making the noise.