Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia)

Abstract

It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioral paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0 deg inclination cue or in a zone with a rapidly changing inclination cue (−3 deg to +85 deg when approaching the feeder and +85 deg to −3 deg when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coil system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions.

Non‐thermal extremely low frequency magnetic field effects on opioid related behaviors: Snails to humans, mechanisms to therapy

“…This is also consistent with reports that suggest it was not static magnetic field but its gradient that was more important for induction of analgesia [Kiss et al, ]. Also it has recently been shown that pigeons can detect changes in a static magnetic field inclination, which would correspond to an induced ELF if magnetic field detector was at a fixed inclination [Mora et al, ]. Currently, we are attempting to investigate this possibility by introducing static magnetic field of differing gradient strengths into the shielded environment.…”

Migratory Eurasian Reed Warblers Can Use Magnetic Declination to Solve the Longitude Problem

“…Juvenile migrants that had not yet established a navigational map also oriented WSW at the capture site but became randomly oriented when the magnetic declination was shifted 8.5 . In combination with latitudinal cues, which birds are known to detect and use [10][11][12], magnetic declination could provide the mostly east-west component for a true bi-coordinate navigation system under clear skies for experienced migratory birds in some areas of the globe.…”

Theoretically possible spatial accuracy of geomagnetic maps used by migrating animals

“…Spring migration of pied flycatchers in these regions is recorded mainly in the second ten days of May, but first birds may be seen from the very end of April [39,40]. The possible periods of imprinting (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and spring arrival (6-20 May) of pied flycatchers are included in the periods we analysed in this paper (July-August and April-May).…”

“…The ability of birds and sea turtles to perceive both total intensity and inclination of Earth-strength magnetic fields has been shown experimentally [21][22][23][24]. If birds [25], sea turtles [15,26,27], possibly also salmonid fishes [28,29] and other long-distance migrants use the geomagnetic field for position finding, the question inevitably arises: what is the possible accuracy of the geomagnetic map?…”