Pigeons Detect Magnetic Fields
Nose Knows North (and South, West and East)

December 1, 2004

Homing pigeons (Columba livia) can find their way home with ease. Scientists have debated how pigeons accomplish this feat. Some researchers have suggested that pigeons smell their way back home. New research shows that pigeons can detect magnetic fields that may aid their travels.

Dr. Cordula Mora and her colleagues at the University of Auckland (New Zealand) taught pigeons to detect the presence or absence of a magnetic field. The researchers trained to pigeons to walk to one end of a wooden tunnel when a magnetic field was turned on and to walk to the opposite end of the tunnel when the magnetic field was turned off. If the birds walked to the correct side of the tunnel, they received a food reward.

After the pigeons were trained successfully, the researchers performed three experiments:

  1. Small magnets were attached to the beaks of the birds.
    Results: The pigeons could not detect when the magnetic field was on or off.
    Conclusion: Pigeons use their magnetic sense to navigate.

  2. The olfactory cavity was anesthetized.
    Results: The pigeons could not detect when the magnetic field was on or off.
    Conclusion The location of the receptors for the magnetic sense is in the beak, not the eye.

  3. The trigeminal nerve or the olfactory nerve was cut.
    Results: When the olfactory nerve was cut, the birds could still detect magnetic fields.
    When the trigeminal nerve was cut, the birds could not detect magnetic fields.
    Conclusion: The olfactory nerve, which carries information about smell, is not necessary for the detection of magnetic fields. The trigeminal nerve is required for the detection of magnetic fields.

These results are in line with the theory that bird beaks contain small magnetic particles called magnetite. Using magnetite, the birds are able to sense the Earth's magnetic fields that provide information about location. Turtles and rainbow trout may use similar magnetic detection systems.

Reference and further information:

  1. Mora, C.V., Davison, M., Wild, J.M. and Walker, M.M. Magnetoreception and its trigeminal mediation in the homing pigeon, Nature, 432:508-511, 2004.
  2. Dr. Cordula V. Mora's web site - she is now at the University of North Carolina
  3. Turtles Find Their Way Using Magnetic Fields - Neuroscience for Kids

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