Who ate all the pies, well the bird seed anyway?

I've been somewhat perplexed by the amount bird food vanishing from our bird table recently. I assumed the magpies had perfected the art of hovering as its pretty much the only way large birds (magpies, wood pigeons and jackdaws, etc.) would be able to gain access to the bird table. However today I happened to notice a brown lump on the table and my theory that a mouse would be unable to get up to that hight was shot down in flames as I watched him fill his cheeks with twice his body weight in RSPB bird seed. He vanished as soon as I opened the window to get a better shot but I'm pretty sure he will be back.