Poison on Hiking Trails?

By an edhat reader

I am a regular hiker on Inspiration trail. [Thursday] morning I (and many other hikers) noticed many dead mice along the trail. This is worrisome as we have not seen that many animals fallen dead all at once before. I hope this is not because of any chemicals or pesticides. Does anyone know? Or who can we alert to look into this and inform the public of the cause?