Several episodes into Earth Sound, thanks to deborahh@cosocial.ca for the brilliant recommendations, a decades old mystery was solved for me. Back when I used to camp, and spend a lot more time in nature, there was this intermittent sound, a beat that started slow, and got faster. It was of such resonance that you could feel it in your chest and in the ground. It’s a ruffed Grouse, and you have to be exactly in its line of sound, and if you’re a female ruffed grouse I guess you get pretty horney. For so many years I wonderd, a bever, some huge mutant scunk about to spoil my year? Now I know. This audio rendering isn’t great, but if you’ve ever heard it and wondered, now you’ll know too
 
youtube.com/watch?v=q0obByQW23…