Professor Thorsten Ritz
Dept of Physics and Astronomy
UC Irvine
Irvine, CA

Monday, November 3, 2003
3:00 pm (CT)
3269 Beckman Institute

Abstract

Migratory birds can detect the geomagnetic field and use it to derive directional information. There are two competing hypotheses for the primary mechanism underlying this physiological compass, one involving magnetite, the other a magnetically sensitive chemical reaction. We will review earlier behavioral studies that suggest that both mechanisms may be used for magnetic field detection by birds. Based on calculations of magnetic field effects on chemical reactions, we predict that the application of oscillating magnetic fields can be a powerful diagnostic tool to distinguish between the two mechanisms, disrupting a chemical mechanism, while leaving a magnetite-based mechanism unaffected. Application of oscillating magnetic fields in a recent test series shows disruption of magnetic orientation of birds, suggesting that their magnetic compass is based on a chemical mechanism. In the end, we will briefly compare the compass of birds with that of other animals.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.