Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: Alandriel on 01/11/2007 17:13:14

Title: Shoals of fish & birds - how do they do it?
Post by: Alandriel on 01/11/2007 17:13:14

All this recent talk about congregating hammerhead sharks has brought up another question:

We humans can barely manage two dimensional travel without accidents alone and any co-ordinated group action takes massive amounts of practise.


How do flocks of birds and shoals of fish change direction so quickly in unison without colliding with each another?

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.princeton.edu%2F%7Eicouzin%2Fbird-flock.jpg&hash=dd113173e5f6549a86052ce42bcb75d4)

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.londonaquarium.co.uk%2Fsystem%2Ffiles%3Ffile%3Dimages%2Fsnapper_shoal.preview.jpg&hash=fe1d928f106c94a9ac04a9f94142e617)

Title: Shoals of fish & birds - how do they do it?
Post by: JimBob on 02/11/2007 00:32:27

I believe the explanation of detection of the change of water pressure for the fish (a line of sensors down each side of the body) but do not know for the birds  ..... for the birds??? OK

Title: Shoals of fish & birds - how do they do it?
Post by: another_someone on 02/11/2007 12:12:51

Quote from: JimBob on 02/11/2007 00:32:27

I believe the explanation of detection of the change of water pressure for the fish (a line of sensors down each side of the body) but do not know for the birds  ..... for the birds??? OK

I suspect there is a slight analogy in birds - if not exactly the same line of sensors.

Birds travel in flocks because it allows the following birds to take advantage of the wingtip vortexes of the bird ahead to give it more lift.  Clearly, as the leading bird turns, so the vortexes trailing behind it will follow the turn of its flight, so the following birds would only need to be able to follow the trail of the vortexes.

Title: Shoals of fish & birds - how do they do it?
Post by: Alandriel on 02/11/2007 15:36:11

Great answers, thanks guys! [;D]

George's mention of trail of vortexes started puting pictures in my head, pictures that got ever more complex each time I'd add yet another bird to my imaginary flock.... sort of perhaps like

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2F9%5Bimg%5Dhttp%3A%2F%2Fxoptimum.narod.ru%2Fresults%2Fincompressible%2Fcylinder%2Fcylinder_re100.gif&hash=fb34b518d1f038c1a6509686fd3f79be)


...just keep on adding more birds/cylinders to that

.. and then I imagine a wee birdie following .... just which trail of vortexes? It would have to know/sense origin and distance..... maybe it does


or maybe I need to move to a colder climate where my head functions better  [;D]

Moderator: Changed your tags so that the image displays properly - hopefully the correct image - otherwise let me know and I'll fix it.

Title: Shoals of fish & birds - how do they do it?
Post by: another_someone on 02/11/2007 16:23:55

Wing tip vortices are more like this:

 [ Invalid Attachment ]  (http://en.wikipedia.org/wiki/Wingtip_vortices)

Title: Shoals of fish & birds - how do they do it?
Post by: Alandriel on 02/11/2007 16:32:46

Thanks for trying to fix the tags - I had given up

... but it seems it still does not work  [:(] it's a weird link that piccie


That piccie of yours: WOW!!! Fab to see with the coloured smoke  [;D]