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Electrophysiological recordings from the ophthalmic nerve and the trigeminal ganglion of the bobolink (Dolichonyx oryzivorus) indicate the presence of units (14% of the spontaneously active cells) that are sensitive to small changes in the magnetic field. The most common response was an increase in the rate of spontaneous activity. The most sensitive units(More)
Extracellular recordings using glass microelectrodes were made from the ophthalmic and supraorbital nerves of a transequatorial migratory bird, the bobolink. The rate of electrical activity was modified in 15% of the spontaneously active units by earth-strength alterations of the horizontal or vertical component of the ambient magnetic field using box(More)
In this study we investigated the effects of a pulsed radio frequency signal similar to the signal produced by global system for mobile communication telephones (900 MHz carrier, modulated at 217 Hz) on neurons of the avian brain. We found that such stimulation resulted in changes in the amount of neural activity by more than half of the brain cells. Most(More)
ability of animals to detect and utilize directional information from the ambient magnetic field has received increasing documentation. Much of the work in this field has been focused on the navigational abilities of homing and migratory birds (Wiltschko and Wiltschko, 1988; R. Wiltschko and Wiltschko, 1995). Of the various magnetoreceptor mechanisms that(More)
Behavior and electrophysiological studies have demonstrated a sensitivity to characteristics of the Geomagnetic field that can be used for navigation, both for direction finding (compass) and position finding (map). The avian magnetic compass receptor appears to be a light-dependent, wavelength-sensitive system that functions as a polarity compass (i.e., it(More)
The retinal photoreceptors of a New World migratory bird, the bobolink (Dolichonyx oryzivorus) were examined using microspectrophotometry. Based on the absorbance spectra of their visual pigments and oil droplets, retinal photoreceptors include five classes of single cones, one double cone, and one rod. The single cones contain a long-wavelength pigment(More)
Sensory information which may be essential for the complex process of orientation of birds is described in this article. The use of vibrational, visual, chemical, olfactory, magnetic cues and their receptive mechanisms, as far as they are known, are explained. Special reference is given to the behavioral and physiological aspects of magnetic sensitivity.
Domesticated Rock Pigeons (Columba livia f. domestica) have been selected for returning home after being displaced. They appear to use many of the physical cue sources available in the natural environment for Map-and-Compass navigation. Two compass mechanisms that have been well documented in pigeons are a time-compensated sun compass and a magnetic(More)