The article discussed avian navigation using geomagnetic field for direction finding (compass) …

• Synopsis
• Introduction
• Magnetic compass
• Magnetic map
• Future work
• Conclusion
• Acknowledgments
• References
• Figures
• Table

Biology Articles » Zoology » Ethology » Mechanisms of Magnetic Orientation in Birds » Figures

Figures

- Mechanisms of Magnetic Orientation in Birds

FIG. 1. Responses of birds to the inclination compass. The behavioral responses indicate that they respond to the magnetic field as equatorward versus poleward. The direction the total magnetic field dips below the horizontal is poleward; north and south are not distinguished. The left figure would correspond to the northern hemisphere and the right figure to the southern hemisphere magnetic field. H_h = horizontal component of the magnetic field vector, H_v = vertical component of the magnetic field vector, = angle of the magnetic field above the horizon, = angle of the magnetic field below the horizon. (Modified from Wiltschko and Wiltschko, 1972)

FIG. 2. Effects of the wavelength (color) of light on a magnetic receptor based on two visual pigments. When the antennal pigment (A) is illuminated at its optimum wavelength, the orientation is in the preferred direction. When the primary pigment (P) is illuminated, the result is a 90° change in orientation. When the two pigments are illuminated equally (E), the result is disorientation. (Based on Deutschlander et al., 1999b)

FIG. 3. Effect of the magnetic field on a radical pair reaction in which the equilibrium between the triplet state and the singlet state is affected by the orientation of the ambient magnetic field. (Based on Ritz et al., 2000)

FIG. 4. Structure of the avian double cone. Each member contains a different visual pigment and optical filter or oil droplet

FIG. 5. Deviation of homing pigeons treated with a magnetic pulse from the control birds when released at different distances from their home loft. The response is not fixed but depends on the distance of the home loft from the release site. (Based on data from Beason et al., 1997)

FIG. 6. Logarithmic sensitivity of a fast adapting magnetic receptor cell associated with the trigeminal nerve in the Bobolink to changes in the ambient magnetic field. (Based on Semm and Beason, 1990)

FIG. 7. Sources of sensory information used for navigation and potential neural interconnections