I like to hear the sound of birds when I travel amongst my orbital and planetary habitats scattered around the outer system.

Most of these settlements are very densely populated - what you might call arcologies in your time - and this generates heat which renders most of them tropical and subtropical climes for the sake of energy efficiency.

The pleasant melodies of creatures like scarlet-backed flowerpeckers and bulbul birds, you know the kind of thing, would be perfect for such an environment. But you may have seen the feeds, birds - like most animals - don't enjoy microgravity too much.

What kind of changes might we expect to see bird species undergo in order to live comfortably in the low- and microgravity conditions of my habitats? More importantly, are any of these changes significant enough that we would see drastic overall changes in bird behaviour (e.g. hopping on surfaces rather than flying)?

Asking for my biotech folks.

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    $\begingroup$ Not an answer, but you need to consider air pressure as well. Lower gravity means a reduced downward force, but absent any other changes your atmosphere will not be as dense, leading to lower air pressure as well. Wings need to be beating against air in order to fly, so lower air pressure translates to less lift. You might get a nice tidy equation where those two factors cancel out, or it might have a notable impact on flight abilities, I don't know. However, you seem to have self-contained artificial environments in mind: you could stuff in extra air to force more Earth-like air pressure. $\endgroup$
    – Palarran
    Nov 6, 2018 at 0:59
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    $\begingroup$ I also lack the scientific credentials to answer this question, but it occurs to me that the orientation issues stressed in your feeds were not as troubling to the birds as the tightly confined space which they were trying to fly in. Given large enclosed skies and the time to mentally adapt to microgravity, I would not be surprised if birds adapt better than we do, since they already spend half of every wing beat in free fall. Your space birds might not always orient themselves as we are used to, but they would soon master flying smoothly and arriving at their destinations without trouble. $\endgroup$ Nov 6, 2018 at 2:49
  • $\begingroup$ Are you asking about short-term behavioral changes or longer-term morphological changes? $\endgroup$
    – Gene
    Nov 6, 2018 at 17:13
  • $\begingroup$ They would likely loose quite a bit of muscle mass, as well as bone strength, as they adapted to an environment with micro-gravity. $\endgroup$
    – ThatCamal
    Dec 13, 2018 at 18:23

3 Answers 3


I am going to assume that these environments have atmosphere since flight let alone sound would otherwise be impossible.

As for flight in zero G

As long as pressure remains the same it might be possible that a bird could mentally adapt to zero g and learn how to fly (would be an awesome experiment for NASA). In order to achieve flight, simply put, you need to create a pressure differential between the top and bottom of the wing. Gravity doesn't necessarily control this interaction, though it does influence it heavily terrestrially. One major way gravity plays a role in birds flight is it defines an up and more importantly a down. The downward pull of the birds mass is energy that is fed into its flight. The wings convert that energy into a pressure difference (gliding).

I'm not sure the loss of that energy totally forbids flight in pressurized zero-g (if it is even called flight at this point, more like swimming). If they can figure out a way to gain directional motion they could then theoretically re-learn how to "fly". In terrestrial flight, gravity ultimately is a negative energy that depletes the system.

Physiologically they wouldn't need wings as large as they have since gravity is no longer pulling them to the ground. If anything they'd probably be better off with highly dexterous fish like fins.


As long as their is a dense enough atmosphere, there is nothing preventing birds from flying, even in micro gravity.

Technically they would not really be flying, it would be more like "swimming"

They would be subject to the usual problems associated with micro gravity (bone density problems, blood circulation problems etc...).


There are a series of genetic modifications that need to be tested somewhere before they are applied to permanent human residents of any place outside of the Earth. Humming birds will face the most problems, and they will refuse to mate while songbirds will probably become duller as there may be a lower light environment, they may have to rely on song for courtship and communication. The 700 nm range of lights for the plants will often leave the habitats cast in a red glare. This light too will keep it warm. Some of the birds such as the Scarlet may become brighter and show more contrast in color with larger feathers for visual displays... I agree with fish finned sparrows. Perhaps more hopping or jumping from branches and the most of the wing beating will be reserved for instinctual dipping and diving. Pigeons roll a certain way in flight, determined by their genetics, and two birds will consistently display different behavior..... Many species will find independent methods of coping, adaptation or loss... Water in the air I imagine will counter many of the lift issues, swimming, especially when moving down or in-system, depending on gravity source. Consider Larry Niven's SmokeRing for effect.


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