My seed feeder is hung just outside my living room window.  Please pretend that the white specks in my hasty snapshot are snowflakes, not crud on plexiglass that refuses to stay clean (but is springy enough to prevent serious injury when a bird tries to fly thru it).

Hey, stupid! The feeder’s empty!

When I am slow to refill the feeder, birds rummage in the tray and sometimes find a seed among the debris that has accumulated.  Then they usually go elsewhere for a while.

Sometimes a chickadee (but never a bird of another species) has a different response.  The chickadee sits on the edge of the tray (looking into my house) and glares at me.  Corvids and parrots are not the only brainy birds.