A Bird that Never Touches Ground

Birds, as we currently know them, build nests and lay eggs on the ground. People and things with sharp teeth live on the ground. There are also things with claws and beaks up in the air, but fewer.

I was wondering if a bird-like animal could exist that would spend its entire life in the air, and only fall to the ground upon death. I already know that birds can sleep while airborne, but I need help with:

• Figuring out a way to explain how my birds (or bats, or whatever) evolved to never touch the ground - I lack a compelling and plausible story.
• The food situation. Unless I also got flying plants (unlikely, given the energy equations), it'll have to be a carnivore preying upon other flying creatures, or grab animals from the ground.
• More specifically, I'm worried about the first stages of life. Perhaps a kangaroo like-pouch for the newborn?
• Finally, I'd prefer to make this flying beast as large as possible for story-related purposes. How big can it get and still fly around the clock, do you think?

(Image above: Northrop still makes the best Quetzalcoatli)

LATE EDIT: Thanks everyone for a great number of good suggestions! All your answers are appreciated, and I wish I could accept two more in this case. Besides @VilleNiemi's answer, which I accepted, I think @Ivy_Lynx's answer deserves more upvotes and I got some interesting ideas from @CortAmmon as well.

posted about 9 years ago

Serban Tanasa‭

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