At first light the magpies are already lining up along the town-hall gutter, each with something small and shiny held as carefully as a library book.
We asked at the kiosk on the square. A woman buying stamps said she used to find spare buttons in the oddest trees. Now a magpie taps the keeper's window, shows the button, and waits for a nod before flying it home to the porch where it belongs.
The keeper pinned a polite note to the ridge: the returns desk is the roof itself, hours from sunrise to the first kettle. The birdhouse, he wrote, has agreed to act as a witness and will nod only once, so nobody has to guess.
By the next morning a single pearl button was back on the doormat, still slightly warm from being carried with such ceremony.