Daft question

Hello all, I visited Leighton Moss with a friend the other day & a discussion arose about the Bearded Tits & when you would be more likely to see them. It was my understanding that they breed on the reserve but that you are most likely to see them when they come to the grit trays around October, when they begin to eat seeds instead of insects; is that correct? What do they eat in the following winter months, or do they leave the reserve. Any info appreciated, thanks in advance.