Birds have Microscopic Compasses that Help Them Sense Earth’s Magnetic Field

Birds have microscopic compasses that help them sense Earth’s magnetic field to find their home and migrate safely. Two new studies have discovered a specific protein in certain bird species that lets them see Earth’s magnetic fields.


The protein which works as a magnetic-field-sensor is called as Cry4, and it’s a class of proteins known as cryptochromes – sensitive to blue light and they are found in both plants and animals. Cryptochromes are involved in the regulating circadian rhythms. Other evidence claims that a sense in birds called magnetoreception allows them to detect a magnetic field.

Atticus Pinzon-Rodriguez, a biologist at the University of Lund in Sweden and lead author of the paper analyzed the zebra finches and researchers from the Carl von Ossietzky University Oldenburg in Germany studied European robins.

Pinzon-Rodriguez’s team studied retinas, muscles, and brains of 39 zebra finches for the levels of Cry4 and two related proteins, Cry1 and Cry2.They found variations in levels of Cry1 and Cry2 while Cry4 levels remained constant, according to the study report.

The researchers wrote, “We also found that Cry1a, Cry1b, and Cry2 mRNA display robust circadian oscillation patterns, whereas Cry4 shows only a weak circadian oscillation.”

“We assume that birds have microscopic compasses and they use them any time of day or night,” says the co-author of the paper Rachel Muheim from the University of Lund biologist.

These two new studies including the zebra finch were published in the Journal of the Royal Society Interface and the robin study was published in Current Biology.