I don’t doubt the bird population has declined. But the stat cited above doesn’t convey any information about the decline.

If you have 30 wild birds in your property and you setup a barn with 70 industrial meat birds inside, you did not necessarily obliterate the wild population.

Fair enough, for sure, but the statistic doesn’t really get at that point directly. It’d be better to say “50% fewer non-agricultural birds were alive in 2019 than in 2018” (or whatever the stat is) if that’s the point they wish to make.