We have a Jackdaw who has for the last 2-3 weeks been arriving several times a day with a beakful of what seems to be mainly droppings and a few downy feathers, leaving them in a line along the top of the fence enclosing our back yard (about 5 meters square) and then wiping his beak on the fence and leaving. The yard encloses a couple of bird feeders, which might be a clue. Is s/he perhaps building a nest the size of the yard, cleaning out a nest elsewhere, marking out territory, or what?
I would guess cleaning the nest. Birds like to deposit the droppings from their nests far away from the nest so as not to draw attention to it. Unfortunately your fence seems to have become the municipal tip for the time being!
A closed mouth gathers no foot.
Hello Band S. I agree with Maisie. We have seen the top of our bin being used for the same purpose.
Thanks to both, you have solved the mystery!