How Migratory Birds Solve The Longitude Problem

Eurasian reed warbler (Acrocephalus scirpaceus).
(Credit: Nikita Chernetsov et al., doi:

How migratory birds detect longitude was a scientific mystery

Figure 2. Magnetic Intensity and Magnetic Declination Form an Excellent Bi-coordinate Grid in Some Parts of the World
The map shows magnetic declination isolines (red; degrees) and total intensity isolines (blue; nT) based on US
NOAA National Geophysical Data Center and Cooperative Institute for Research in Environmental Sciences [more]. The breeding range of Eurasian reed warblers is shown in yellow. The black curve indicates the autumn migratory route of a typical Eurasian reed warbler from the Baltic region based on ringing recoveries. The map is a Mercator projection of the WGS84 geographic coordinate system. (doi:10.1016/j.cub.2017.07.024)
Eurasian reed warbler (Acrocephalus scirpaceus).
Martien Brand / CC BY 2.0.)
Research setup (cages and magnetic coil) on the study site.
(Credit: Dominik Heyers, doi:
Visual abstract.
Nikita Chernetsov, et al., doi:

Reed warblers are the first animal known to use magnetic declination to address the longitude problem




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𝐆𝐫𝐫𝐥𝐒𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭, scientist & writer

𝐆𝐫𝐫𝐥𝐒𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭, scientist & writer

PhD evolutionary ecology/ornithology. Psittacophile. scicomm Forbes, previously Guardian. always Ravenclaw. discarded scientist & writer, now an angry house elf