The study presented here was conducted in order to analyze the role of the direction of celestial rotation in the development of stellar orientation in young migratory birds. The test birds were garden warblers, Sylvla borin, which leave their breeding ground on a southwesterly compass course. The birds were hand-raised and, during the premigratory period, exposed to an artificial 'sky' in the local geomagnetic field. For the control group C, the star pattern was rotating in the natural direction, with the centre of rotation and magnetic North coinciding. For the three experimental groups, the star pattern was rotating in the opposite direction; for group E1, the centre of rotation coincided with magnetic North, for group E2 the centre of rotation was at magnetic West and for group E3 it was at magnetic East. During autumn migration, the birds were tested without magnetic information under the same, now stationary, sky. All four groups were able to use stellar information for orientation, but only the control group preferred the normal southwesterly course. The three experimental groups, in contrast, all oriented towards a significantly different direction, preferring due south. The results for group E1 showed less scatter than those for the other two experimental groups. These results indicate that the direction of celestial rotation is crucial for the development of the normal migratory course with respect to the stars in young garden warblers. Establishing the species-specific southwesterly migratory course requires an interaction between celestial rotation and magnetic cues; this interaction appears to depend on the natural direction of celestial rotation. Rotation in the reverse direction allowed the birds to respond only in a manner that oriented them away from the centre of rotation.
In the field: an interview with Sönke Johnsen
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Sönke Johnsen is a Professor at Duke University, USA, investigating visual ecology and he talks about his experiences of collecting transparent animals while blue water diving and in a submersible, as well as outrunning Hurricane Katrina.
Call for new preLighters
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preLights is the preprint highlighting community supported by The Company of Biologists. At the heart of preLights are our preLighters: early-career researchers who select and write about interesting new preprints for the research community. We are currently looking for new preLighters to join our team. Find out more and apply here.
Graham Scott in conversation with Big Biology
Graham Scott talks to Big Biology about the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade.
Trap-jaw ants coordinate tendon and exoskeleton for perfect mandible arc
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Trap-jaw ants run the risk of tearing themselves apart when they fire off their mandibles, but Greg Sutton & co have discovered that the ants simultaneously push and pull the mandibles using energy stored in a head tendon and their exoskeleton to drive the jaws in a perfect arc.
Hearing without a tympanic ear
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In their Review, Grace Capshaw, Jakob Christensen-Dalsgaard and Catherine Carr explore the mechanisms of hearing in extant atympanate vertebrates and the implications for the early evolution of tympanate hearing.
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