On a ridge in the Wasatch Mountains in Utah, at about 6500 feet, at dusk.
In late September, elk are in their 'rut', which means it's breeding time. A few different sounds, from a kind of squeaky bark maybe from an elk cow, to the long and primal bugle call of the buck. Here the order is: real elk, then Ray's call, then real, then Ray, an almost frustrated whimper, and Ray chirping back. The extended bugle with those weird smooching sounds at the end, as you can hear, Ray says (echoed by my Dad) is the buck getting pissed off.
Note: the different calls that Ray performs you'll hear as the louder, more close-up bugles and squeaks, as they're obviously closer to the mics. The far-off, awesome bugles of the elk were almost beyond the sensitivity of my equipment. You might be better with headphones for this one.