I did this over the weekend. I set up my WA21 about 30yds away and off to the side some. I also used my mojo and slipped just into the tree line. I started with mobbing sounds then switched to crow distress sounds. I switched back and forth and never turned it off. Had several hours a day shooting them. I used a full choke and #6 cheap walmart loads. Earleir in the week I set up an owl decoy and several dead crows and played owl/crow fighting and crow dying sounds, killed quite a few then also. With crows I have found cover and not moving help a lot.