Cover image

Cover: European robins tested in orientation cages change their directional preferences under different wavelengths and intensities of light. In the study by Rachel Muheim, Johan Backman and Susanne Ackerson (see pp. 3845-3856), young European robins exposed to 560.5 nm green light (left graph) were well oriented into the seasonally appropriate southwesterly direction, were completely disoriented under 567.5 nm green-yellow light (middle graph) and showed a shifted orientation under 617 nm red light (right graph). The lower graph gives the spectra of the monochromatic lights used in the study, the full-spectrum light produced by the xenon arc lamps (white line), the spectra of an incandescent light bulb (orange line) and the natural spectrum shortly after sunset (violet line). The picture of the European robin was kindly provided by Jens B. Bruun.