After investigating the issue already in 2 other papers (Karwinkel et al 2022a, J Roy Soc Interface; 2022b JEB), we conducted a third experiment trying to understand how migratory birds navigate using the Earth's magnetic field. In previous studies, short but strong magnetic pulses were used to alter the hypothesised sensory magnetic particles. As a result, the birds showed this change in their migratory behavior. However, these studies lacked appropriate controls as electrical effects were not taken into account. In this study, a controlled experiment was designed to accurately test the effects of the magnetic pulse component, but despite a large sample size of 250 birds, no effects were found. However, the study sets new methodological standards for future studies to investigate how birds use magnetic information for navigation.

Karwinkel T, Winklhofer M, Allenstein D, Brust V, Christoph P, Holland RA, Hüppop O, Steen J, Bairlein F, Schmaljohann H (2024) A refined magnetic pulse treatment method for magnetic navigation experiments with adequate sham control: a case study on free-flying songbirds. J. R. Soc. Interface.2120230745. http://doi.org/10.1098/rsif.2023.0745

The new paper, published in the prestigious journal "Biological Reviews", presents a novel and comprehensive concept of how the magnetic sense is used by songbirds in their migration ecology. It is aimed at both beginners and experts in this field. Beginners can get a first overview of the confusing primary literature on hypotheses about the magnetoreception of songbirds. For experts in the field of magnetoreception, it offers a new ecological perspective on their research, facilitating appropriate experimental design and interpretation of results.

Karwinkel, T., Peter, A., Holland, R.A., Thorup, K., Bairlein, F., Schmaljohann, H. (2024) A conceptual framework on the role of magnetic cues in songbird migration ecology. Biological Reviews https://doi.org/10.1111/brv.13082

For this year's fieldwork in the project „Navigation in translocated birds", Annika Peter and her team set off for Pape in Latvia. The aim of the project is to find out whether a magnetic pulse affects the compensatory ability of virtually translocated migratory birds, represented by reed warblers (Acrocephalus scirpaceus). It is hypothesised that a magnetic pulse interferes with the magnetic particle-based mechanism used by the birds to navigate their migration. The project is being carried out in co-operation with the University of Latvia.