So, bought a call from my friend Matt at "MPK custom calls" in England the other month, tested it, and it's really good on carrion crows and rooks, but also jackdaws, gives a nice raspy sound. The basic model isn't expensive either at £25.00 (plus p&p), but if you prefer exotic, he can make them in almost any wood you wish, and laminated exotic woods too.
He also does duck, geese, and predator calls too.
My my other two calls I got from Nils at "LOCKSCHMIEDE" in Germany a couple of weeks back.
weather hasn't been brilliant so haven't been out to try them except for a short mornings shoot the other day.
That said, he does TWO crow calls, one a general crow call, and one for "older" crows.
again, available in plain, or exotic woods. Both give a nice raspy sound, with the "older" call being a slightly deeper tone.
That said, the one shoot I did with the "general" call was reasonably successful (as I was mostly after pigeon) and I got 35 downed for the morning using the call.
All lol three of these calls would be a worthwhile addiction to your armoury of calls.
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If it moves and is legal but also moral, SHOOT IT !!