The barking is toward the end of the video:
Gray “foxes” are as distantly related an animal can be to a domestic dog and still be in the dog family.
Yet they do bark.
Granted, it is used almost solely as an alarm call, whereas domestic dogs use it for a wide variety of purposes.
This sound is a bit disconcerting when one hears it in the woods in the middle of the night.
It’s a deep, raspy sort of bark that one might not recognize as a bark.
But it is one.
These particular foxes were filmed in Upstate New York. In the Eastern United States, there are only two kinds of wild dog that are of this size. One is the red fox, which actually is a fox, and the other is the gray fox, which honestly needs a better name. Inali is the Cherokee word for the species.
But good luck getting that name established in the English language!
It is upset at being surprised and is rebuking.