You can see Grouse from south of Bellingham year round. The North Shore isn't pristine natural habitat for anything.
That's a fact but there are those that believe it is pristine or will revert to that if it's all left alone to just them. It's the perception that is important.
Switch said:"Some conditions require A LOT more light (cold winter hazy/misty nights).
Some trails require more light because of their composition. Pure gravel lights up well, but duff and leaves don't.
Climb with one light on during the long ascent, turn on the 2nd for the quick descent. Nocturnal creatures need not really be bothered. "
Very true. Wet trails on a wet cloudy night are very dark and visibility is poorer. And not everyone sees as well at night. I think I have good night vision because I don't really have problems, but I have friends that don't ride at night because even with good lights they don't see well and stumble and crash around a lot.
I don't know if a passing light bothers nocturnal critters. I do see more mice and other small mammals at night with my dual HID's than when I had lesser lights. I suspect the animals don't care that much and become habituated rapidly. I did watch a cougar on highway 99 last winter gnawing on a deer that I saw it capture from the headlights of my car. It did not appear to be the least bit concerned with me watching from 30 feet off, or from the other traffic going by. Mind you it was probably pretty concentrated on holding dinner down until it expired.
Debate? Bikes are made for riding not pushing.