i get good response to my fox pro with the crow fight and crow distress. i can call birds in pretty regularly with it.
make sure you get a few decoys too - crows are smart, especially if anyone in the area also hunts them.
i like to put something on the ground and arrange a couple decoy's around it like they're on the ground picking at something, or at least interested in it.
if you can get a guard/sentinel bird decoy up a tree in the area, all the better.