General Discussion
Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsGuaranteed to Blow your Mind (Seriously)
Last edited Tue Oct 2, 2012, 12:58 PM - Edit history (3)
Species of birds have a few different ways of navigating during migration. Some have biological magnetic detectors. Some use culturelearning from the previous generation.
And some use the stars.
It appears that these birds are born knowing the stars, and how to determine north from them. But somebody very clever realized that birds cannot have evolved an innate star map of north and south because the Earth's axis has a large but very slow wobble that cycles every 26,000 thousand years.
Polaris, the star we call the north star, wasn't the north-most star 13,000 years ago. (The visible star that Earth's axis most closely points to.)
26,000 years is a mere blink in evolutionary time. The sky changes too fast for evolution to have created an instinctual knowledge of which star is the north star.
It was a genuine challenge to evolution. How can birds be born knowing which star to follow north?
When we got night vision cameras and such to study birds we found out what evolution had done. These birds are not born with an innate star map. They are born with an innate method for finding the north star!
These baby birds sit motionless in the nest, night after night, staring up at the sky. Over enough hours of observation there is one star in the sky that appears to move the least during the night, and that is the north-most star. And then they learn the pattern of stars around it so they can find that star from different orientations, and so on.
If that doesn't blow a person's mind then nothing will.
This is one of many things that animals appear to be born knowing, but actually have an instinct for learning. (Much like our language instinct. We are not born knowing chinese or english, but we are born with an instinctual method for learning the language we grow up hearing. And toddlers with no language taught to them will make up a language, in the way some identical twins create a language only they understand.)
On edit: I might as well include information about our changing north star. It's 26,000 years... I know it was 20-something.
The identity of the pole stars gradually changes over time because the celestial poles exhibit a slow continuous drift through the star field. The primary reason for this is the precession of the Earth's rotational axis, which causes its orientation to change over time. If the stars were fixed in space, precession would cause the celestial poles to trace out imaginary circles on the celestial sphere approximately once every 26,000 years, passing close to different stars at different times. However, the stars themselves exhibit motion relative to each other, and this so-called proper motion is another cause of the apparent drift of pole stars.
http://en.wikipedia.org/wiki/Pole_star
Happyhippychick
(8,379 posts)progressoid
(49,991 posts)ellie
(6,929 posts)Avalux
(35,015 posts)I would love to share it with my kids and people I know...absolutely mind-blowing. As human beings with our big brains, we think other animals on this planet are so simple, so mindless; this certainly proves otherwise, and it also reminds us of our interconnectedness and oneness with the universe. Thank you for sharing.
cthulu2016
(10,960 posts)was in Richard Dawkin's book The Ancestor's Tale. (One of many amazing things in that book)
Avalux
(35,015 posts)And you did a great job writing that from memory.
HopeHoops
(47,675 posts)The butterfly that leaves Maine won't make it to the tree in Mexico. It lays eggs, and the new ones emerge, and often lay eggs and die on the way. It can take up to four generations before they get to the tree, but the still do. Then they come back with the same generational issue. Our yard is a common stop-over for them. I've seen more this year than in many recent ones. The official count is up as well.
defacto7
(13,485 posts)Just joking. This is fascinating, but what is their centre in the south?
lastlib
(23,239 posts)just a WAG.....
cthulu2016
(10,960 posts)there are southern star-navigating birds. There is, at this time, no bright star aligned with the south pole so the method wouldn't be so useful.
Voice for Peace
(13,141 posts)night after night, staring up at the sky.
Over enough hours of observation there is one star
that moves the least in the sky, and that is the
north-most star. And then they learn the pattern
of stars around it, and so on.
YAY *stars and birds*
BlueJazz
(25,348 posts)I wonder if light-pollution can screw up their whole system.
Spitfire of ATJ
(32,723 posts)....and for all we know they have actual language and speak to each other.
I have a friend who owned a parakeet that I swear had a multiple personality disorder. It would go back and forth in two voices as if it was in an argument and a third voice would seem to tell the other two to shut up. Then it would be silent for a while and then a fourth voice would start up and before long a fifth would get going in response and the one that stopped it all would seem to have given up and gone away.
Now she has a sun conure that loves to be cuddled and speaks actual words it has learned.
nadinbrzezinski
(154,021 posts)but I swear the two birds have taught me Conure.
They make themselves very well understood, thank you very much. And the Nanday is VERY SMALRT.
No, not because he is my bird, nope, he has learned to do things like connect and disconnect USB ports, (BOING), and he has learned to get out of his cage, and also to let me know when he needs food and water. I kid that I sort of speak a foreign language, Conure.
Spitfire of ATJ
(32,723 posts)...then when it's time to go to bed it gets in one of those fuzzy tents on it's back and talks to itself repeating all the little phrases it knows to put itself to sleep so you hear it saying, "bye bye, I luv you, night night, hey!, see ya!, there ya go, hello" etc...
Good training treat: chopped walnuts.
nadinbrzezinski
(154,021 posts)She speaks herself to sleep too, just in conure.
Now that bird, like Alex, is using language in context.
And a sun on shoulder right now, and my quake detector at my feet.
I need to check supplies, he's accurate.
Spitfire of ATJ
(32,723 posts)Things like greeting calls, departure calls, etc. One was "happy to be alive".
It showed each type of common pet bird and the conure was the number one noise maker on occasions but not decibel. Parrots are louder but less frequent.
nadinbrzezinski
(154,021 posts)And with training our birds are actually quiet.
lumberjack_jeff
(33,224 posts)"If those birds were transplanted to a world in another galaxy they would still know what the North star was on that world."
The sky only looks like it does from this solar system.
cthulu2016
(10,960 posts)Even with a completely different night sky they would still be identifying the star that appears to move least, which would be the star closest to that world's axis of rotation... that world's "north star"
lumberjack_jeff
(33,224 posts)I would suggest the following edit;
"If those birds were
cthulu2016
(10,960 posts)I was thinking species but yes, the first individual adult birds would be lost.
That sentence was extraneous anyway, so I took it out altogether.
Care Acutely
(1,370 posts)nadinbrzezinski
(154,021 posts)one of them is all aloof and all that. But by now I am convinced he can sense quakes. We had one overnight, that none of us silly humans could have felt, he is becoming attached, again.
So of course, time to check my quake supplies, and no, I am not kidding, the last two times... we had a cluster and the next to last a 7.5 in Baja that did all kinds of fun to El Centro.