Years ago I was involved in doing bird surveys in various parts of MN but at 75 now my hearing is not what it used to be. My eyesight is still excellent so we do a lot of fun birding all over MN. Probably my wife and I are the most active birding couple in the state and are in the top ten in bird species seen in the state. You get to big lists be doing it for a lot of years. In our case about 35 years and counting. Hopefully many many more.