How to track: Like the other trackable hunter pets, you will not be able to see him when he's up. He is completely stealthed. In order to locate him, you will need to find and follow his tracks - tracks that thankfully only hunters can see. Once you've found his tracks you'll need to follow them until you don't see any more. This is where I like to wait and watch where I think that he'll be walking next. Often times you'll see a new track appear right in front of you - this means you've found him!
Once you find him, the only way to see where he is, will be for him to walk through a flare. Don't throw your flare down on top of the track he just left, throw it a little further out in front of where you think he is. When he walks through your flare he will become visible. You can take this opportunity to tame, or you can throw a Hunter's Mark on him - which will keep him visible to you when he goes back into stealth. Hunter's Mark will make him visible to you, but only you when he's in stealth.
Glimmer's tracks are called "Flooded Tracks", and they really look nothing like any track you would expect to see from his weird bug feet. (I guess they're better than paw prints though.) His tracks are also not particularly difficult to find toward either end of his path. They are light in color on ground that is dark green through most of his path, making them stand out a bit. Like other beasts' tracks they do not stay up indefinitely; the furthest ones behind disappear one by one as new tracks are created.
(Currently his tracks must be followed backwards in order to find him. Hopefully this will be changed in the near future. I will change the info right here on this page if I find out anything new.)
Glimmer's path is the shortest compared to all of the other trackable hunter pets. It takes him about 27 minutes to move from one end of the path to the other. When he reaches the end of his path, he simply turns around 180 degrees and heads back in the direction he came from. Although a short path is good, Glimmer's path is highly affected by phasing. As a matter of fact, about half of his path goes through several phased areas including: Fox Grove, Orchid Hollow, Shadybranch Pocket and Serpent's Heart. When he walks into these phased areas you will not be able to see or interact with him or even see his tracks. I was able to track him through his whole path to get some screenshots though, even with the phasing issues using eagle eye from unphased areas.
I'm not sure which quests change the phase of these areas yet. I couldn't see him move through the phased areas on a brand new 85 having done only a single quest in the zone. I also tried on one of my characters who had done a large portion of quests throughout the zone with no luck. I'm not sure if these phasing issues will carry over to live, but just in case I marked the phased area on the map below. The best bet to nab this guy is to search either end of his path for tracks (red line on map). If there are no tracks at either end, wait about 15 minutes and check again; there is a good chance he was passing through the phased area. If you still don't see tracks he's probably not up.
|Red & White checkered line = phased area. Click map to Enlarge|
|The above screenshots show Glimmer nearing the western end of his path just north of Camp Gormal, and then turning around.|
|In the above left pic Glimmer is moving east past Nectarbreeze Orchard. In the middle & right pics he is heading into Fox Grove where he phases out.|
|The above screenshots were taken using eagle eye. They show Glimmer moving east through Fox Grove.|
|In the above pics Glimmer is continuing through another phased area, Orchid Hollow.|
|Above from left to right: Glimmer has just exited his phased area, and is moving north into The Aboretum.|
|These last screenshots show Glimmer Heading toward the northeastern end of his path and turning around. The exact place he turns around is where the 'H" is on your map where it says The Aboretum.|