Late in the season, I love shooting crows. As mentioned, go on the internet and you will find recordings of their different calls. As I recall, there were five and I learned them all but mostly use two. I have also used decoys to bring them in. I hunt them alone but if a group of you can string out along a hill side, call them in and have a ball. ...
http://www.crowbusters.com/begtechn_dc.htm
What I do;
In full camo, I find a good place to hide on a hillside. Make sure to have some overhead cover, if possible. All in an effort to be well hid.
I give the come here call or I found food. repeat two or three times and wait.
Pretty soon, the "scout" should come in and he will not make a sound, just looks around. Make sure you spot him. Be patient and slowly take your first shot. If he flies off before you had a chance to shoot, let him and again, wait. Repeat the first call and try again.
Okay, I've shot the scout and he's down. Wait a little and give the distress call. Stand by cause here "they" come. Just keep shooting and when they fly off, repeat the distress call and start shooting again. Once you get them in this cycle, they just keep coming back and take a long time for them to leave. All the time you are doing this, try to stay hid and don't over-call. ....
By the way, when hunting alone, I only use a .22lr rifle of MK-Ii pistol. With the group, use shotguns. ..
Be Safe !!!