The ducks we are hunting have migrated down from the northern reaches of the central flyway. They've made it past sooner, cornhusker, and dakotan hunters. So, they've heard plenty of calling. The guides here call sparingly and they call softly. If the birds are coming in, they don't call at all and they don't call at birds that are far away. A few chuckles for redheads and a soft whistle or two for pintails is as far as they'll push it. Any more aggressive calling won't change the birds' minds and it will probably only spook them.