Some times gobs will gobble coming to roost if there's several toms competing for the hens. Guess they're letting the gals know where there flyin' up to roost. They also might be wantin' to receive a "quickie" before flyin' up!!
I have killed more than one in this situation.
"Chasin' gobblers has a lot in common with dealing with a wife, 'bout the time ya' think ya' got 'em figured out, they change the rules!!!"