The finches completely emptied their sock. There were dregs at the bottom and two of them were working together trying to get the last millet-seed out. So we added Orchard Hardware to the Saturday morning shopping run and got a refill bag. Now they are happily emptying it again, although for some reason it's now much rarer for two birds to be on the sock at once. And the housemate says the finches have themselves been hoovering up the spilled seed beneath, rather than let the mourning doves do it. Or the dog.
.