RE: roosting birds...
If only for a good shock gobble call, you need to get a coyote howler. You can then shock gobble turkeys easily after sundown and I' ve shocked ' em as late as an hour and a half after sundown. I' ve never had very good luck with the crow call as a shocker, but the howler works very well after sundown and also works well very early in the morning before they are gobbling on thier own.