Very nice vid, Art!
In my eye, its from mid July, from the looks of the whiteish loose hairs on their backs and short fat black velvety antlers.
I think they are herded up close to keep the bugs off. Caribou in Summer favor the snow patches then as mosquito's and biting bugs are not the only things biting, they have warble flys hatching from the skin on their backs and doing their annual hair shedding.The scabs that are healing on the back side must itch with all that going on and no way to scratch that itch......
The month of August they have all of that healed and nice chocolate colored hides, and the sores are healed, so we can scrape them of fascia and meat and use them to make things.