You all can tell I'm borred today right
Locators are a very important call to have with you and the crow is one such call that I find is one of the "Go to Calls" in the locator world. What I have found is that different crow calls tend to work differently and I'm guessing the pitch is the answer of why they work at times.
I carry the Quakerboy Cranking crow and as well a Faulks and I can do it also witrh my voice too, want to hear

J/K
anyway I find that they all work at different times. I've had one work over another at times and then the very next day the other one would work over the one I used the day before. Be fexable and have a number of different locators because they have the right time at sometime.
Toss a DSD at them