"The birds define where the face of the 2-heavens starts because some birds can’t fly."
Penguins. May be a different medium (water: 800x denser than air), but as far as experts in biomechanics & physics are concerned (aerodynamics/hydrodynamics), they can still fly.
Puffins shouldn't theoretically be able to fly (PROTIP: Bumblebees), but they can. They can also 'fly' a la penguins in water too. [/smartarse]
...and that's where you FAIL. Right from the start. It gets better, folks...:
"at that time there were some birds that could fly on the edge of what God defines as outer space. I’m not sure if there are still birds that do this during migratory flights or not. Does anybody know?"
You could always ask Chuck Yeager. In 1963, he took up a Lockheed F-104 Starfighter, to try and beat the altitude record (previously set by a Soviet pilot). Upon approaching the edge of our atmosphere, nearing sub-orbital space, his engine flamed out, he lost control and went into a flat spin; having to eject. Near, as you say, 'the edge of what God defines as outer space'. Jet engines (such as that in Yeager's Starfighter) requires air (via it's intakes) to maintain fuel ignition.
At that altitude, there is little to no air whatsoever.
Thus said flame-out. If Yeager's Starfighter couldn't 'breathe' (Yeager even had to wear what is effectively a 'spacesuit'; as do USAF/NASA Lockheed SR-71 & U-2* pilots today), then how the fuck can said migratory birds? You tell me.
Moral: Aeronautics education. Get one.
*- In a one-off documentary by the BBC, "Top Gear"'s James May (a.k.a. 'Captain Slow') goes up in a Lockheed U-2 (a two-seater version):