 |
 |
Bird Navigation
Name: Abhishek
Status: student
Grade: 4-5
Location: ND
Country: India
Date: Fall 2012
Question:
How does bird return to their exact place from which they had started the migration? I know only the little bit information that E.M. wave may help them to recognize the path but actually I want to know how does it takes place?
Replies:
Abishek
I can’t tell you how birds really navigate during migration because there is no communication channel between birds and humans.
What we do know is that they don’t have little pockets in which they keep magnetic compasses and maps, and they have been doing their navigation tricks long before the Global Positioning Satellite system was established.
This article from Wikipedia is the most comprehensive presentation on the subject:
http://en.wikipedia.org/wiki/Bird_migration#Orientation_and_navigation
It talks about birds navigating their migration flights:
According to the position of the Sun
Magnetic material has been found in the brains of birds suggesting they navigate relative to the Earth’s magnetic field plus magnetic anomalies along their route surface of the earth. For example a mountain range may distort the magnetic field in such a way that the birds can detect that and they use that anomaly as an interim waypoint.
Visual clues from landmarks probably also serve as a major input to their navigation, but that doesn’t explain how birds navigate during the night.
Here is an excerpt from the above article that gets a little more technical:
“Migratory birds may use two electromagnetic tools to find their destinations: one that is entirely innate and another that relies on experience. A young bird on its first migration flies in the correct direction according to the Earth's magnetic field, but does not know how far the journey will be. It does this through a radical pair mechanism whereby chemical reactions in special photo pigments sensitive to long wavelengths are affected by the field. Note that although this only works during daylight hours, it does not use the position of the sun in any way. At this stage the bird is similar to a boy scout with a compass but no map, until it grows accustomed to the journey and can put its other facilities to use. With experience they learn various landmarks and this "mapping" is done by magnetites in the trigeminal system, which tell the bird how strong the field is. Because birds migrate between northern and southern regions, the magnetic field strengths at different latitudes let it interpret the radical pair mechanism more accurately and let it know when it has reached its destination.[28] More recent research has found a neural connection between the eye and "Cluster N", the part of the forebrain that is active during migrational orientation, suggesting that birds may actually be able to see the magnetic field of the earth.[29][30]”
You can click on the blue parts to get amplification of those issues.
Best of luck to you.
Sincere regards,
Mike Stewart
The ability of birds to navigate is amazing and not completely understood by scientists. This article gives an overview:
http://www.birds.cornell.edu/AllAboutBirds/studying/migration/navigation
That many birds use magnetic fields in some way is well known but exactly how they do it is subject of much research. Here is some recent information:
http://www.nytimes.com/2012/04/27/science/study-sheds-light-on-how-pigeons-navigate-by-magnetic-field.html
J Elliott
Click here to return to the Zoology Archives
| |
Update: November 2011
|
|
