Alex finished his sandwich and brushed the crumbs from his pants.
I'm sure they're just dropping him crumbs.
At Christmas time he scattered crumbs of bread under the trees, so that the tiny creatures could feast and be happy.
When I was building, one of these had its nest underneath the house, and before I had laid the second floor, and swept out the shavings, would come out regularly at lunch time and pick up the crumbs at my feet.
Make a stuffing of bread crumbs as above.