I was wondering if a full aquatic bird could exist and not be on, or return to land at any developmental stage, basically, to be completely independent of land. I already know that there are some aquatic animals that can rest one side of their brain at a time, making sleep not an issue, but I can not figure out the rest:
Figuring out a way to explain how a bird could evolve to be completely independent from land. The best story I can come up with is that the birds evolve into the early stages of a terrestrial bird, but then that area became flooded. However, I doubt such a scenario is realistic, and it would then be easier for the to evolve into a crane or stork-like creature.
I am not sure what would change in their lungs that would accommodate them being submerged for such long amounts of time. More specifically, what would have to happen to keep their lungs from collapsing at great depths?
Also, I'm worried about the first stages of life. Perhaps carrying its eggs in its mouth like a grouper?
Finally, I'd prefer the bird to have some sort of mechanisms that might allow them to communicate under water , like dolphin whistles. But I cannot create a viable explanation for their nostrils moving all the away atop their heads
Any help would be greatly appreciated. Thank you