UKC

I've often wondered about how much g force various types of birds can withstand, a fairly obvious example being a peregrine pulling up out of a dive (I've seen one estimate claiming 25 g....) but after spending nearly an hour yesterday watching lapwings I feel they must be up there with the best because of the sheer violence of their direction changes. They really do seem to be able to turn on a sixpence and do it time after time with apparently very little effort. Any more suggestions?

https://centerofthewest.org/2020/01/28/adaptations-for-speedy-life-style-of....

It's interesting. Peregrines have many other amazing features beside gforce resilience. As an order, falcons have been around for 30+ million years, plenty of time for evolution.

It's a very different thing to pure aeronautics, but the first thing that comes to my mind is gannets diving.

youtube.com/watch?v=1Cp1n_vPvYY&

Apparently, juvenile peregrines have slightly longer wings than adults so that it's easier to learn how to fly (like a peregrine) without crashing.

Presumably adults are a bit like modern fighter jets, flown on the point of instability to maximise manoeuvrability.

Lapwings give an extra to their displays with their wing movements and their calls. Howver, been watching Barn Swallows and they turn fast. Quite slow in relative speed (c/w the likes of falcons) which I read was normally cruising about 45 mph but can peak at 70 mph. They roll very quick so must have a high level of g force for a short time.

Not flying but does the Great Spotted Woodpecker not experience some of the highest deceleration forces on their head?

70mph with 2m radius turn gives 45g. Swallow being chased by sparrow hawk missed the window when I walked into the conservatory. The sparrow hawk full braking wing tail feet outline was on the window dust with no damage to the bird.

A couple of things occur to me (and I've also spent the last week being mesmerised by lapwing displays).  The first is that the actual changes in absolute velocity are probably less than they seem.  We tend to visualise speed by scaling to the size of the animal and imagine what that would be if it were a sports car or a fighter plane, but that isn't how physics works.  I often marvel at the manoeuvrability of dragonflies.  How can they possibly stop from full speed and instantaneously reverse?  It seems impossible, but, just in terms of the forces generated, are they actually changing velocity so much quicker than you can?  Obviously, if an aircraft could do the same scaled up  velocities in terms in body-lengths per second, the forces would be unsurvivable.  Actually, doesn't f=ma tell us the same thing?

Second, even if some very large forces are generated by small animals, (like a flea, for example), as well as having small masses, they are disproportionately strong compared with human scale musculoskeletal structures (because cross-sectional area increases as the square of length, and mass as the cube).

So lapwings, dragonflies, peregrines, gannets and woodpeckers are amazing (and gannets and woodpeckers have specific adaptations to cope with their brains decelerating) but not physical laws are being violated!  Being small has its advantages.

That may work out at something like 45x the acceleration due to gravity, but the force exerted depends on the mass.

What he said. If you get the chance, watch an aircraft, then a flying display of a scale model of that aircraft. Try it online. Even with a skilled model pilot, the model is zippy and nippy and just not realistic. If the fullsize takes two minutes from appearing as a spec in the distance to roar past and pull into a huge climb passing clouds at ten thousand feet and covering two counties, the model will whizz by in twenty seconds and with best efforts reach a thousand all in the length of the car park. 

As the scale goes down, the speeds and distances drop, the g-forces go crazy high, the relative strengths go crazy high (mass and loads fall as a cube while lengths and speeds fall linearly.) By the time you're getting down to insects, fluids are beginning to behave more like water or honey; flight becomes more akin to swimming. Which is why we get the old b''cks about bumblebee flight being impossible; if you take large-scale aerodynamics and scale them inappropriately small, they give "surprising" (ie. rubbish/non-meaningful) results. 

Physicists feel free to sob at this characterisation. It'll do for aero engineering. 

Y

Probably. Interestingly, their beaks are not directly fused to the skull, but connected by rubbery cartilege, which acts as a shock absorber.

While sitting in the shade in a kind of barn at a farm shop cafe at the weekend, I had the rare treat of watching a big buff-tailed bumblebee flying about low above a dusty floor.  Looked a bit like this.   Just because it's not impossible doesn't mean it's not impressive, they're powerful little animals.

not according to latest research suggesting evolution has minimised the wasted energy of shock absorbtion? (1000g+)

https://www.nytimes.com/2022/07/14/science/woodpeckers-brains-shock.html

Well well - I (clearly) hadn't see that research. Thanks

DON'T... ANSWER... THE... QUESTION....

This reminds me of something I read in the book "The Shrinking Man" (1956!) which I've never forgotten.

Once he's shrunk to some tiny size I think he falls off a step or desk or something and to him it looks like falling off a tall building and he assumes he is about to die, but he just hits the ground with a thud and realises something about F=MA and he weighs very little now so the force is much smaller. I always think this is why creatures like ants, spiders, etc. can fall a distance which would be like sky diving for a person but then just land and walk off like nothing has happened.

I think we're talking about a similar concept!