My Cute DuCo Swim Freely First Video

The wail call is specifically saying "If you can hear me, call so I know where you are too". It is done with the bill closed and only with a slight opening along both edges

Note the grizzled muzzle on the first loon. It's not an indication of age. It is the beginning of the loss of breeding plumage for that year, and it first shows around mid-September (here along the 47th north latitude). The Common Loon goes through one molt a year, being completed as it overwinters in coastal waters. By spring, it is fully dressed in breeding plumage again.... and ready for the dance floor again!