And make sure you're actually hearing them when they do bugle - I've hunted with newer elk hunters that caught maybe 1 in 5 bugles that I heard. Some people have a hard time filtering for those real faint ones, or they have a hard time being quiet and still enough. This obviously applies for responses to location bugles, but also just while you're out for the rest of the day. There's nothing worse than stopping suddenly because you might hear a faint bugle... but your buddy's following too closely, not paying attention, and is cracking too much brush for you to hear anything.