Magnetic Compass Orientation

ByRichard Nissen 5 June 20215 June 2021 Reading Time: 1 minute

This paper is a very good overview of the thinking about avian migratory navigation and acknowledges that birds use all the cues that are available to them to navigate successfully.

Magnetic Compass Orientation in a Palaearctic–Indian Night Migrant, the Red-Headed Bunting

Summary

The earth’s magnetic field, celestial cues, and retention of geographical cues en route provide birds with compass knowledge during migration. The magnetic compass works on the direction of the magnetic field, specifically, the course of the field lines. We tested Red-headed Buntings in orientation cages in the evening during spring migration. Simulated overcast testing resulted in a northerly mean direction, while in clear skies, birds oriented in an NNW (north–northwest) direction. Buntings were exposed to 120° anticlockwise shifted magnetic fields under simulated overcast skies and responded by shifting their orientation accordingly. The results showed that this Palaearctic night migrant possesses a magnetic compass, as well as the fact that magnetic cues act as primary directional messengers. When birds were exposed to different environmental conditions at 22 °C and 38 °C temperatures under simulated overcast conditions, they showed a delay in Zugunruhe (migratory restlessness) at 22 °C, while an advance migratory restlessness was observed under 38 °C conditions. Hot and cold weather clearly influenced the timing of migrations in Red-headed Buntings, but not the direction.

How do dogs know the right direction and yet when they do know the route home, why do they not take it but sit and wait to be found?

Examples with my Welsh terrier Rhubarbe. Living in Paris, he and I used to walk in the Champs de Mars by the Eiffel Tower at least twice a week and sometimes more. He knew the way there and back by heart. He walked without a lead and once in the park, which is not closed,…

Another idea

I am fascinated in Animal Migration. I have attended very learned arguments about this: they have found that birds have magnets in their beaks for instance. But as you investigate these arguments they just do not work right. For successful migration you need to know when to go and where to go. Terns for instance…

A Sense of Direction – some more examples

I hold the view that animals, the ancient peoples and the Aborigines navigate perfectly well without compasses. This we often call a sense of direction. People with a sense of direction very seldom get lost even on dark nights even in unfamiliar territory. Not everyone has a sense of direction but those who do rely on…

Does your dog wait for you (their owner) to come home? – An experiment

Please participate! An experiment to see how dogs respond to their owners. Does your dog wait for you (their owner) to come home? If this is your case please participate in this experiment. Introduction Rupert Sheldrake is a hero of ours and has written a book we have reviewed “Dogs that know when their owners are…

Our co-editor Antonio Nafarrate has recently written these remarks

Following the 2016 Royal Institute of Navigation (RIN) Conference on “Animal Navigation”, Dr. Painter claims that after some 50 years of work, the Magnetic “mechanism is not fully understood”. In my judgment, it will never be, because there is no such mechanism. The Geomagnetic Field (GMF) is only a minor perturbation to the true navigational…

Summary

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