Navigation is like a rope
One way to look at navigation is to think of a rope.
A rope is made up of many strands each are often tiny weak and short. The Incas made bridges over great canyons using straw wound together to make great strong ropes that last for ages.
Each fibre of a rope must be wound together into a tight bundle and then twisted into strands that are bound together into a single rope. The rope has properties that are completely different from the individual strands.
For natural navigation all the information that can possibly be used has to be integrated into developing a solution.
The important difference with navigation is that there is always a beginning of the journey and an end. Different factors are at work at different times in the journey.
Different parts of the journey need different skills:
Starting out
You need a bearing to set out in roughly the right direction. Many animals do just that. They have the confidence to set out based on “knowing which way to go”.
In the middle
You are trying to get better information. You are looking for landmarks. You are searching for more clues to help support your initial direction. Some of these are things like wind direction, where the sun is etc. The clues are often in quite low resolution.
Near the end
You suddenly starting picking up landmarks. This confirms where you are and where you need to go. The resolution of clues gets finer and finer.
As you approach your destination
You are integrating neighbourhood clues and using a different part of the brain: the Hippocampus. Sense of smell is often critical too. But, in the end you just recognise your destination and there you are!
Ingo Schiffner comments:
GPS?
A better analogy would be our technical compass, it has a needle and the four directions imprinted on the bottom plate, all you need to do is line up the needle with the direction you want to go to. The difference is that migratory birds know only one direction, the migratory direction .
Ingo Schiffner comments:
The Analogy isn’t bad, but you should point out that unlike the rope, navigation makes use of different “materials”, i.e. senses to achieve this kind of stability. This also ensures that in an relatively unpredictable environment, and our world is mostly unpredictable, stability is achieved by assuming that while some factors may be subject to random fluctuations, others will remain stable. This means on one day it might be a good idea to use the sun as a compass on another day you might be better off using a magnetic compass.