In reply to Doug:
A friend had a peanut feeder out for the birds, which kept being raided by *something*: he routinely found it on the opposite side of the house from where it should be, smashed up on on the concrete path.
So, to find out what was happening, he staked it out - and eventually saw two jackdaws fly in, lift the thing of its hook and, holding it with their beaks, fly off *together* (they had obviously figured out it was too heavy for either of them to lift individually), after which they dropped the thing from height onto the path, and proceeded to fang into the nuts.
A quite incredible story - but true.
For those who haven't read it, Konrad Lorenz describes sophisticated behaviour by jackdaws in his classic book 'King Solomon's Ring.'
Post edited at 21:48