Grey Wagtail chick

A Grey Wagtail searched for insects on the path near the bridge and brought them to a chick.

This seems to be the only chick and it's the first time I've seen it. It's also the first time I've seen the male of the pair nesting here. The female is the bird which has often appeared on this blog in recent months; apparently she was hatched here last year.

A male Greenfinch called from a dead branch at the top of a holly tree beside the Long Water.

I photographed a female in the same place to days ago, so there is a pair here.

Two young Long-Tailed Tits waited in a bush in the Dell ...

... while a parent was on the other side of the bush looking for insects for them.

A young Great Tit was also waiting in a tree at the northwest corner of the bridge.

The Coal Tit at Mount Gate didn't see me until I'd gone well past its usual place, and hurried along to perch in a lime tree by the Albert Memorial and demand a pine nut.

Ahmet Amerikali photographed the Reed Warbler at the Italian Garden collecting insects in the plants behind the stand of reeds. I'm pretty sure that the leaves are those of Hemlock Water Dropwort, Oenanthe crocata, the most poisonous plant in Britain ...

... but later I photographed a Painted Lady butterfly happily drinking nectar from a flower at the top of the same clump. (There are a lot of little white-flowered umbelliferous plants similar to this but PlantNet was 93 per cent certain of the species of the flower.)

Evidently it isn't poisonous to butterflies -- though it might make the butterfly toxic to birds, and if so the butterfly's bright colours would be aposematic, a warning to birds not to eat it.

Later: looking this up, I read that Painted Ladies aren't toxic, but their colours are still a protection because they mimic those of the Monarch butterfly which is toxic from feeding on milkweed. This would be an example of Batesian mimicry, a harmless species mimicking a poisonous one. But the butterfly here, feeding on a poisonous plant, might really be poisonous and an exception to the rule.

Or perhaps the nectar is the only part of the plant that isn't toxic: see this article.

Hemlock Water Dropwort was used for poisoning and executions in ancient Sardinia. It causes death in a few hours hours by muscle constriction leading to suffocation. The agonised expression on the faces of victims as all their muscles tighten was called risus sardonicus, the Sardinian smile, and is the origin of our expression 'sardonic grin'. (Don't try this at home, children.)

The female Blackbird of the pair on the south side of the Dell stared from a bush.

The male Little Owl at the Round was in his usual place in the lime tree, even more fluffed up than usual.

Perhaps this is a hostile display to the human intruder photographing him. He hasn't done it in the past two years I've known him. But I was standing near the dead tree when I was taking the picture, and if indeed the pair have managed to nest here he would have seen my presence as a threat.

Both the young Grey Herons were down from the nest and standing on the wire baskets surrounding the island ...

... while the parents had returned to their nest and were having a staring match with the heron in the lower nest.

The Great Crested Grebe chick on the Long Water waited beside the nest, where one of the adults was resting.

One of the Coots nesting under the bridge brought a twig to the nest while the sitting bird played with the most recent offering, a crisp packet. It's not clear whether any of the early chicks have survived here.

The female Mute Swan from the Long Water had taken her cygnets under the bridge on to the Serpentine. Her murderous mate, the boss of the entire lake, can go anywhere he likes.

Let's hope he keeps to the Long Water. He has often killed goslings and there are few on the Serpentine this year. The Canada Geese are down to one brood of three ...

... and a single gosling, which was resting with its parents on the edge.

The brambles are flowering, attracting large numbers of Honeybees.