Alot of it is down to the bird Noisy! some take to the Black stuff like a duck to water and some have to be made. I know a old falconer who took many Rooks/Crows with a Lugger, also one of the main birds used on them before the Hybrid craze was a Pure Peregrine which got the job done in style.....
I have never flown a Peregrine at crows but have flown a Male Gyr/Saker, Female Pere/Saker and a couple of Female Pere/Prairies. If I had to make a choice from the birds that rocked my boat it would be the Peregrine/Prairie's! I liked their style and comitment aswel as their sheer aggresion towar