Interesting stuff Steve, and your deke looks realistic.
Have you tried baiting for maggies? A rabbit carcase ,suitably opened up will often attract the little sods, a road kill would fit the bill. Of course using a 4.10 does severely limit your range ,and ,as we know ,all the crow family have tremendous eyesight, you need to be suitably cammoed up for the job, I once shot eleven maggies in one morning ,shooting out of an old war time pill box.A little later on, you should have more success, as the young branchers start to appear ,they are not as wary as their older brethren.