Grapes are best for wine!!!

We don’t get a great deal of variety regarding visitors to our bird table but there does seem to be a hierarchy regarding who gets there first. And last.
Usually the sparrows or blackbirds are first on the scene.
Next is a robin or two
The starlings then take over, about thirty or forty of them, squabbling over the food.
But, if a jackdaw makes an appearance, the rest scatter.
And when the jackdaws take their leave!
It’s back to the robin.
Just how do they know there is food on offer???