it literally cannot though, unless it becomes some other form of life that doesn't need oxygen, that's the whole thing with this analogy, it's ironically suited to the discourse

Ha I didn't even count oxygen in the mix; it could hold its breath maybe? j/k, what's for sure is that I don't see how a biological entity could ever achieve escape velocity from self-powered flight, because, well, physics.

That, or they "keep improving every month" til they become evolved enough to build rockets, at which point the entire point of them being birds becomes moot.

It would need to: * Survive without oxygen * Propel itself without using wings * Store enough energy for the long trip and upkeep of the below * Insulation that can handle the radiation and temperature fluctuations * Have a form of skin that can withstand the pressure change from earth to space and then the moon * Have eyes that don't pop while in space

It would need to become something literally extraterrestrial that has not evolved in the 3.7b+ years prior.

I wouldn't say it's impossible, but if evolution ever got there that creature would be so far removed from a bird that I don't think we'd recognize it :p