The Popping/Nervous grunt or bark as some call it (not to be confused with a warning bark) is used by all elk in varying situations. By experiencing this sound in its many forms by elk under different situations one can come to his or her conclusions that if it's good enough for the elk to use it under particular situations then it will also work for us hunters! This sound is used out of Curiosity or Wanting Identification & at times to Create Excitement. But it's not held to just that! Bulls will use it in front of a screaming bugle or at the end of one instead of a series of grunts. Why? Because not only are they trying to intimidate the other bull but he wants to see this new challenger. At times a bull will give his threatening scream & give a couple coarse barks trying to run the intruder bull off! Elk will also vary volume in its use depending on nervousness or lack of it. Many times you will hear an elk give a soft one then another with a bit more volume. Too, I've seen calves squeal this sound along with small chirps as they were hopping & darting around with a sense of excitement & the more mature cows not even giving them a glance. Seeing things like this firsthand really helps us to know when & where we can best utilize such sounds.
We've taken many bulls with the use of the popping/nervous grunt, timing of sounds is key, too, they must fit the encounter or fit a method of use. Do not confuse this sound with a "bark" a bark is used by elk as a warning to others in the area, it will be given by them several times in just a few seconds or within 60 seconds & they are getting further away, other elk may also chime in with this warning as they exit the area. Nervous/Popping grunts are given in a single note fashion, in most cases they're no closer than 30 sec apart, generally closer to a minute sometimes more as they remain in the area waiting for a satisfying visual or response.
Maxxis31, shows an interesting video that really should not be overlooked! Between the 3min--4min mark you will hear a cow giving an "estrus buzz" this shows it's a sound used by elk to keep in contact with or looking or inviting other elk their way, this is not a sound used when a cow is ready to be bred! Nice clip! Thanks.
ElkNut1