They are fascinating. Out on the front porch late while puffing on my pipe, a huge white owl (barred?) landed on the gutter about two feet above my head. With their keen eyesight I'm sure he must have seen me but he perched there for a few moments before moving on.
Where I used to live the county has a raptor center which has cages for injured birds of prey to recover from injuries. Anyway, my son's Eagle project was to build a cage for owls. It was about the size of a single car garage. We made it with good lumber and chain link fencing. Its first resident was a great horned owl that would clack its beak if you did anything to upset him.
Interesting.
I often watch the TV show, North Woods Law, so I have heard that clacking before.
After watching my first episode of Mountain Men, I had to look up Marten.
I remember thinking... What the hell is a marten?