Bob cats, mountain lions, etc used to have the entire US as their range. I suspect the bird population boomed after we got rid of the cats (100-150 years ago).

Bob cats, mountain lions, etc used to have the entire US as their range. I suspect the bird population boomed after we got rid of the cats (100-150 years ago). Now that we have house cats they’re dropping again. Boom-bust cycles for animals are common. I try to reflect what the natural order was 10,000 years ago and reflect. 20,000 years ago, there was an ice sheet over North America - ie no birds. https://en.m.wikipedia.org/wiki/Laurentide_Ice_Sheet https://en.m.wikipedia.org/wiki/Laurentide_Ice_Sheet