Game and Country in Selkirk sell round multicatch crow traps. They get them from Ireland! A quick phone call to them may be worth a shout. Far better than the standard Larsen trap. Advantage is they catch 3 at a time. I have 2 in use. Best thing is designed for crows but work on magpies. Tad bulky though however will just go in the back of a 4x4.
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