Three of the Tawny owlets were in a horse chestnut tree on the north side of the Flower Walk opposite the California bay. Here are two of them.

I couldn't find the elder owlet or either of the adults, but no doubt they were nearby. The growing horse chestnut leaves are already thick enough to make spotting anything quite difficult. When I came back later, these owlets had moved and I couldn't find them again. They often make short flights from tree to tree in the daytime.

This is one of the Mistle Thrushes with a nest near the Serpentine Gallery, on the edge of the bicycle path.

It is used to passing traffic and will come quite close to you as long as you don't seem to be stalking it. If you stand still for a few minutes it will forget about you in its search for worms. Passing Carrion Crows, Magpies and Jays, on the other hand, get the full dive-bombing treatment.

Hostilities continue among the Mute Swans on both the Serpentine and the Long Water.

Thanks to Paul Sawford for this dramatic picture of a mature swan attacking a younger one. The victim is one of last year's cygnets; as you can see, it is still tinged with grey and its bill has not yet taken on the adult orange colour. But it is quite old enough to be beaten up by one of the dominant swans.

These mating small white butterflies are, technically, Small White butterflies (Pieris rapae).

This and a larger species equally unimaginatively named the Large White (Pieris brassicae) are the notorious 'Cabbage White' butterflies whose caterpillars eat gardeners' prized vegetables. During its short life, a Small White may fly as far as 100 miles -- though mostly it will stay where it started. In 1939, some complete idiot introduced it to Australia, at Melbourne. Three years later, the species had reached the west coast of Australia some 1,850 miles away, having gone through about 25 generations. It has been a pest in Australia ever since.