They didn't start "humming" until around 8:30 this morning but they got so loud later on that my hunting partner went over to the edge of a river bottom at 10:00 to make a few calls before we left. Only 75 yards from me I could see him running his slate but I could not not hear his calls over the locust noise and he told me he cranked down on his slate.
Wonder if the noise has any effect on the birds?