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Comment by djtriptych | Hacker News Reader

I've been birding over the pandemic and learning about how they fly. Watching them, it starts to become clear just how skilled and efficient they are.

This tech demo is amazing, but my mind immediately compares it to things like the ruby-throated hummingbird migration, in which a 5 gram bird[0] flies 500+ MILES nonstop over open water, on maybe 2 grams of fat storage.

Then they feed by hovering so accurately that they can reliably thread a 1/8" beak into a moving 1/4" target.

They can do this directly into 20 mph headwinds [0]. Also in rainstorms where they are constantly getting pelted with their bodyweight in wet missiles every few seconds.

They can also fly 30mph in level flight, which in body lengths / second is ~4x times faster than an SR-71.

[0] US nickels weigh 5 grams, for comparison.

[1] https://www.kqed.org/science/28759/what-happens-when-you-put...

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The other one that amazes me is the Petrel family, that digest fish and process oil from them and store it in their foregut. This allows them to fly long distances - like, Falkland Islands to Svalbard kind of distances - without really stopping.

The thing that gets me about it is they brew this fish oil into something with the energy density of *diesel* that they can then digest, and I have this mental picture of some kind of Endura-DI Shearwater flapping, clattering and smoking, all the way across the Atlantic in search of its breeding grounds...

You might enjoy this book: https://mitpress.mit.edu/books/simple-science-flight-revised...

(I did, a lot.)

oh wow. thanks!

Thank you, this definitely goes on my reading list!

Cool six minute video from SmarterEveryDay on dragonfly flight mechanics - https://www.youtube.com/watch?v=oxrLYv0QXa4

If you don't watch the whole thing, fast forward to the slow mo at ~4:35. I still remember watching this for the first time 9 years ago...geez.

There is a crappy pdf of this floating around that I read before buying this. Deffo worth it but for those who want to try before you buy it’s worth ‘binging’ it.

While hummingbirds are amazing, I think we will have to model out systems more closely to birds of prey. Most birds can’t carry much extra weight, until you get to raptors and some sea birds.

We would be after something that can carry a payload such as a salmon, a coconut, or a human.

Or a moose. My sister was bitten by a moose once.

Nature is lightyears ahead of tech when it comes to power efficiency.

> Then they feed by hovering so accurately that they can reliably thread a 1/8" beak into a moving 1/4" target.

They can do this directly into 20 mph headwinds [0]. Also in rainstorms where they are constantly getting pelted with their bodyweight in wet missiles every few seconds.

What I find amazing is that chickens appear to possess a sort of natural optical stabilizer - which will keep their heads still even when the rest of their body is moved. [1]

If this is a regular feature of bird anatomy, it would explain how a lot of their precision during flight is archived.

At least this made it click for me how an eagle is likely able to keep track of some tiny rodent hundreds of meters below it while hovering in mid-air and bracing against wind, turbulences, etc.

I suspect we have the same mechanism, but only applied to the eyeballs, not the whole head.

[1] https://youtu.be/Rgy-CbrUNkw

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