Squirrel

I think we might have made a mistake.
I saw a bird feeder on clearance at target and bought it as an extra for the garden. It's a really tall one with clever blocked openings so the little birds have to put their beaks inside to get the food. It is surrounded by a pretty twirling wire for the birds to perch on.
It's been up in our garden, hanging from a corner of the house, for about two months. There was no bird action until today.
It was full this morning - and now this evening it is less than a third full. Some of the seeds are scattered all over the floor underneath the feeder.
At one point there were 7 little birds perched on the feeder and 2 squirrels underneath.
So....how did the seeds empty out so quickly. Was it just a lot of hungry little birds and they managed to knock some out?
Or do we have clever squirrels who managed to knock the feeder hard enough to spill then all over the floor and then gobbled most of them up?
Hmmm. Maybe I need to set up a video camera?!