For the trap ; crows, magpies, jackdaws, jays, rooks, best time of the year as they are very territorial and a decoy will attract them.
As for crows,
I shot one crow stealing chickens eggs in view of its partner over a year ago. Since then and even yesterday I have been recognised and harassed by this particular bird , it will make a lot of noise and fly at me, except when I have the bang stick with me !