This was fascinating to watch in person. Every time the Hawk moved, so did the Squirrel. The Squirrel always tried to stay on the trunk and well within the branches, while the Hawk tried to wait for an opening. The Hawk was clever and tried moving to a different tree a couple times to lure the Squirrel to the ground, but the Squirrel didn't fall for it, and was too scared to leave the tree.
This video here is a compilation of two longer videos I took together (you can tell because it will shift to landscape). The lighting/quality aren't great, so I picked the most visible parts. If you turn up the volume a little, you can hear the Squirrel mewing, especially after about 2 minutes. Also about 2 minutes in, another person enters the screen and is startled to hear the mewing, so he starts watching too.
Unfortunately I do not know who won the standoff.