On the farms that I hunt... There is a huge drop off in gobbling after the first 2 weeks of season. I believe the turkeys gobble less for 2 reasons. Most of the hens have been bred so they aren't needing to call as many to them by gobbling. Also...they know they are being hunted and don't want to give away their location by gobbling. Usually they gobble throughout the season on the roost at least several times...but after those first couple weeks....those gobbles on the ground are few and far between.