Grey heron and Song Thrushes

[glsammy]

I witnessed some strange behaviour yesterday at a nearby Heronry. Whilst the Herons were on the nest they were constantly being surrounded by a group of song thrushes, which seemed to be trying to get at something in the nest. I took as good a shot as I could of the nest to see if they'd used any twigs with berries on, but couldn't see anything like that.
Any ideas what the thrushes might have been after?

[GuyF]

There's a chance the thrushes were mobbing the Heron, I've seen crows do it so thrushes might also do it. I've heard of Herons eating small birds so maybe the thrushes felt threatened. Not sure though, sounds like interesting behaviour!
Guy

[glsammy]

Thanks Guy. It seemed to be more the nest the Thrushes were after, for instance two were resting on a branch beneath the nest and flying up into the nest for a second or so to return to the branch and repeat the act. Very strange!
One bird did get quite close to the Heron, too close as the heron struck at it.

[Gill Catton]

herons will have a go at eating anything that moves given the opportunity, so mobbing is possible or perhaps the song thrush (how many? could itave been a pair?) had adopted the nest or part of the nest as it's own - perhaps the heron aspect of the nest had been abandoned until very recently....
House sparrows have been known to nest in the base of active heron nest...

[Lance Morgan]

It is well known that herons as well many other large birds typically birds of prey are mobbed by other smaller birds particularly corvids. It could be that the thrushes were using the heron nest which is mainly built from branches and twigs for protection or a perching point to make their 'attack'. (IMO)