BIEB 166 Lecture Notes - Lecture 11: True North, Savannah Sparrow, North Magnetic Pole
8 Nov 2013
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Document Summary
For escape from stormy weather, safer in deeper water. Sharks make nightly migrations to feed, with the same path everyday. Sensing and respond to the earth"s magnetic field. Highly correlated with the deviation of the magnetic field. On the cloudy day, when the magnetic distractor is on, they cannot orient their path. Even the magnet is turned on in a sunny day, it doesn"t distract the bird. Calibrating to the earth"s magnetic field for long distance migration. Trip restlessness of migratory birds in spring and fall (measure with emlen funnel cage) In the fall, they tend to go south, and in spring, they tend to go north. Travel at night, can see stars (which gives true north) The number of degree for the true north changes through time. Finding true north: axis of rotation of celestial cues--polarized light during the day, stars at night. Artificial stars, change location as the experimenter wanted.
