====== Avian navigation ======

Many species of birds can very reliably navigate over large distances, even from places they have never been to, and return to their desired destination, often over hundreds or even thousands of kilometres.

Homing pigeons, for example, can very consistently find their way back to their adopted roosting place - even when they have been physically removed hundreds of kilometres away - and often without any knowledge of the removal route.

It's known that they use a variety of methods to navigate - including

  * Detection of the Earth's magnetic field
  * Olfactory clues
  * Star patterns (at night)
  * Visual 'map' memories, 
  * Ambient light polarisation
  * Low-frequency sound identification
  * Landmark following (e.g. man-made roads etc)

No consensus exists amongst biologists, however, regarding which systems dominate, their interactions, and how the birds maintain the extreme accuracy that they have. (See : [[https://en.wikipedia.org/wiki/Homing_pigeon#Navigation|Wikipedia]])

A 2024 study from Bangor University, UK, found that a species of Reed Warbler (//Acrocephalus scirpaceus//) appears to predominantly be using fine-detail variations in the Earth's magnetic field to navigate.

>Eurasian reed warblers (//Acrocephalus scirpaceus//), can determine their position based on two magnetic field components that are also associated with direction finding, i.e. magnetic inclination and magnetic declination.\\ \\ [...]\\ \\ Based on our current results, it appears that birds can use a combination of magnetic inclination and magnetic declination to locate their position, even when the values of these cues do not match the geospatial variation of the total intensity of the Earth’s magnetic field. This suggests that a majority rule may apply, or possibly that the total intensity of the magnetic field does not form a part of the navigational map of birds."
>\\ See: [[https://royalsocietypublishing.org/doi/10.1098/rspb.2024.1363|Proceedings of the Royal Society, B, Volume 291 Issue 2034]]{{:oa_padlock_grn.png?16}}

Note that the way(s) in which the birds (and other animals) somehow sense the Earth's magnetic field in very fine detail is currently unclear. See : [[content:life_sciences:zoology:magnetoreception]]

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Also see [[content:life_sciences:zoology:turtle_migration|Marine Turtle Migration]] and [[content:life_sciences:zoology:monarch_migration]]