Hive account@carinewhy we had same problem as well when we explored the glow worm in Te Anau. It is just to avoid noise and also flash light over the glow worm . However , we discovered some decent amount of glow worm in Milford Sound jungle while we were trekking. It is just few meter away from the bunker we stayed . It was amazing feeling to witness them closely . You should go for a breeze walk when sunset and try to discover some hidden places like under the rocks near by the creek if possible .