Birds and animals are amazing.
Clearly, both the starfield and the magnetic field are important cues for birds to migrate. But human activity has the potential to disrupt these. Artificial light at night from cities reduces visibility of the stars and moon. In other animals, such as dung beetles and sandhoppers, this has been shown to negatively affect navigation abilities.
What’s more, artificial electromagnetic signals – such as those coming from radio towers or even from electric currents that power everyday devices such as kettles – can also confuse birds’ ability to detect the natural magnetic field. We may be giving birds a double dose of pollution that even their fail-safe systems can’t overcome.