Like, I’m aware of there being exceptions like Penguins, Ostriches, and Bats. But in general, why is there such a distinct land/air split between mammals and birds? Why don’t mammals share the ground with ecosystems of plant- and meat-eating walking birds? Why didn’t we get birds that evolved to slither like snakes, or tunnel like rodents? Why isn’t it (land+sky) all just mammals, where we’d have parrot- and vulture-like bats that don’t lay eggs? If we started the simulation again, might things like this evolve?
New Zealand bird life in a nut shell
Yeah we have plenty of flightless birds here (or rather HAD), birds burrow and ground nest, bats that spend a lot of time ground foraging, insects that grow to the size of small rodents, carnivorous snails (https://www.youtube.com/watch?v=ubNm5M2-LAc) and more