Experimental Analysis of Oriented Migratory Behavior in Passerine Birds.
Final rept. 1 Apr 63-31 Mar 69,
NORTHWESTERN UNIV EVANSTON ILL DEPT OF BIOLOGICAL SCIENCES
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Despite much variation oriented migratory behavior was observed sufficiently to explore the role of environmental and physiological factors in its occurrence. It was correlated with season and physiological state and independent of a view of the sky, stars, sun, horizon, and the earths magnetic field declination. No perception of magnetic fields was found in a variety of experiments using the birds activity pattern as an assay. A circadian rhythm plays a highly significant role in the measurement of day length and in the induction and timing of migratory activity. A circadian rhythm was found in EEG studies in free-moving birds, in the gonadal response, in the pineal gland and in the hypothalamus. Migratory activity is probably regulated by time-measuring activities of the brain, the activities of the pineal that are related to synthesis of melatonin, and fluctuation of norepinephrine in the hypothalamus. Author
- Anatomy and Physiology