Mystery animal... Please identify.

[LucidSilverback]

I am looking for some assistance identifying an animal which I (and one of my cats) discovered in my backyard. I shot a video of it in hopes someone could illuminate me as to its species. http://youtu.be/ShiBHbKQSwA The creature is obscured by roots and foliage so, I'm hoping identification can be made based on the sound it makes in the video. I know various marten species inhabit this region, and I have even been fortunate enough to have personally witnessed the elusive fisher not once, but twice! So, I know they frequent the area.
I'm located in southern Maine and there are more details in the description section of the posted video.
Thanks in advance!

[JackBean]

just added on PC?