Officially this is an estimate, but having been where these animals live, I believe we can have an exact count. Keep in mind that when we say “globally” this means a tiny region straddling the border between Rwanda, Uganda and Congo.

We are talking about a few families of gorillas, some of which are tracked daily. There is a massive conservation effort on these animals, at least in Rwanda and Uganda, they all have names and I don’t think a gorilla is born without someone knowing about it

I believe it also helps that they live in social groups, aside from some solitary males.

So we're tracking (population / avg_group_size + misc_males) objects, as opposed to the entire population.

Example on the other end would be snow leopards (130+ sq km) and grizzlies (380+ sq km), which are mostly solitary and have huge ranges.

If there are really 1063 I would think conservationists could know about almost every one individually. That's smaller than the high school I went to. I know they are spread out over a wide area in a dense jungle but I think it would be possible.

This film explains it all: https://www.imdb.com/title/tt0095243/

At the worst point their numbers dropped to the mid 100s.

The main threat to them is poaching, and local wars.

For further info: https://gorillafund.org/