Peculiar crow behaviour.

Hello everyone - I registered for this discussion group to see if anyone can answer a question I have regarding the behaviour of crows.

We live in an urban environment and despite having a very small front garden, we have three crows who visit regularly.  Two seem to be a couple and one is a loner - the other two normally see the loner off if they're around when he visits, however a few days ago, we noticed some strange behaviour on our CCTV cameras.

We have a box with rat poison located in the garden - normally the crows ignore this, however on this occasion, while the couple of crows were in the garden, the loner came down, grabbed hold of the rat box and started throwing it around the garden.  The couple then seems to join in on this "game".  My wife went out, took the box off them and placed it back in situ, but within minutes the crows were back throwing the box around and then they were joined by a group of the local pigeons!

Was this some sort of pigeons vs crows game or what exactly was happening here?