In December 2018 while trekking through the Tetons, I got the treat of a lifetime... for me anyway.  While prepping dinner at camp I heard music to my ears.  You'll need to turn the volume up and listen carefully as I was only using my phone to record.  The second video is the best I think and in some you will hear the annoying sound of my DSLR camera taking pics.  They howled for couple hours until I drifted off to sleep.