On a beautiful sunny day, the female Tawny Owl was sunning herself in the usual bay tree. When she heard me crashing about in the flower bed trying to get an angle for a picture, she lazily opened one eye for a few seconds.

I didn't manage to see the rest of the family. Owl spotting in evergreens is a new and tricky sport.

The male Little Owl was also out in his nest tree enjoying the sun. As usual, he had his back to it, so that he could feel the warmth on his feathers but not have the sun shining in his eyes.

I wonder whether the rather human-like eyebrows that Little Owls have are an adaptation to their diurnal habits, to shade their sensitive eyes.

The Great Crested Grebes nesting under the willow tree near the Serpentine Bridge now have one egg.

When I passed the nest, the male was turning the egg over to keep it evenly warmed. Both parents take an equal share of sitting duty while their mates go fishing, first for themselves but later for the chicks as well. The active bird will also bring back materials to build up the nest. This nest includes a whole plastic carrier bag laid horizontally, which you can see in yesterday's picture but today had sunk below the surface as the constantly sagging nest was built up. Grebes must be the only birds that find plastic bags useful, rather than a hazard. Coots may add a brightly coloured or silver bag to their nest as an ornament, but don't use them in construction.

The Great Crested Grebes at the east end of the Serpentine have now built a new nest sensibly sited inside the netting and made out of reed stems.

The second-year Great Black-Backed Gull, which I had not seen for some weeks, has returned to the Long Water. Here it is offshore from Peter Pan, eating a slice of white bread that someone has thrown in for the ducks. Gulls will eat practically anything.