On the front of the shelter is a notice saying that numerous porcupines have been sighted inside and outside of the shelter. As of last night, one porcupine came into the shelter after dark...spent the evening chewing up the shelter....even to the point of climbing up to the second level of the bunk beds...and then calmly sat (apparently sleeping) on the lateral rail next to the shelter journal area even after the sun was up.
Given that (at least this one critter) the porcupine was not afraid of people (there were two people in the shelter when the critter first came in; and one of the hikers spent the night in the shelter with the critter), was not put off by noise and/or bright lights; it is probably time for someone from fish and game (or whatever) to live trap it and get it to a new non-shelter location.
I like critters as much as anyone...but I would not want to try to hike out from Cove Mountain shelter into Duncannon....with a porcupine quill or quills in my face and/or eye.