Magpies and Crow.

We have been watching entranced for days now the attempts of a couple of magpies to construct a nest. The jumping up and down on branches to try to break off twigs and then trying to manoeuvre those twigs to the right spot. Anyway today they are building quite well when along comes this crow and seems to decide he wants the nest. Is this common practise because it seems very unfair after they have worked so hard.

 http://youtu.be/n7J7qsPgtBE