OMG! That's the way hunters call over protective Mama bears! The Mama bear believes her cubs are in danger!
Perhaps, but the tone of a cub call will doubtless be different from a loon call. The tone is controllable. There's bear in Maine and I never heard of anyone be confronted by bears when calling loons. Hopefully that was not because those caught were eaten. And this sound is made by the passage of air in and out of that chamber not by and vocalization of the caller.
You're not putting me on now, are you?