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Published on: January 26, 2009
Olfactory navigation in homing pigeons: the last challenge
Anna Gagliardo1, Paolo Ioalè, Maria Savini
1Department of Biology, University of Pisa, Pisa, Italy. agagliardo@biologia.unipi.it
Annals of the New York Academy of Sciences
|August 19, 2009
Summary
Pigeon homing relies on olfactory cues for navigational map development. Surgical disruption of the trigeminal nerve (V1) did not impair homing, indicating olfactory input is crucial for navigation.
Area of Science:
- Animal behavior
- Neuroethology
- Sensory biology
Background:
- The olfactory navigation hypothesis for pigeon homing has been challenged by findings of magnetoreceptors in the upper beak.
- These receptors are innervated by the ophthalmic branch of the trigeminal nerve (V1).
Purpose of the Study:
- To investigate if navigational cue reliance is influenced by developmental sensory exposure.
- To determine the role of the trigeminal nerve (V1) and olfactory nerve in pigeon homing and navigational map formation.
Main Methods:
- Pigeons underwent surgery at a young age to section either the ophthalmic branch of the trigeminal nerve (V1) or the olfactory nerve.
- Post-surgery, birds were trained with flights to assess their homing performance.
Main Results:
- Section of the ophthalmic branch of the trigeminal nerve (V1) did not affect homing performance in pigeons.
- Disruption of the olfactory nerve indicated that olfactory cues are essential for the development of the navigational map.
Conclusions:
- The trigeminal nerve (V1) and its potential magnetoreceptors are not essential for pigeon homing.
- Olfactory input during development is critical for establishing the navigational map used by pigeons for homing.
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