The invisible: the orientation of the European robin (Erithacus rubecula).

The European robin (Erithacus rubecula) is a small passerine bird in the family Muscicapidae, recognizable by its striking bright orange breast and face. Many of its populations migrate to warmer areas in the winter, but until now scientists have been unaware of the mechanisms that allow the robin to orient itself.

This species feeds on insects, worms, and fruits, making it an important pest controller and seed disperser. Robins have a remarkably territorial, yet confident, behavior, making them easy to observe even near urban areas.

It is very common in Europe, where it has widely distributed populations. Scientists have investigated the orientation mechanisms of birds, thanks to the migratory phenomenon of this species.

They were able to identify the protein cryptochrome 4 (ErCRY4), which is present in the retina of robins (the inner, back part of the eyeball). This protein is both a photoreceptor, reacting to light, and a magnetoreceptor, responding to the Earth's magnetic field. Robins sense the magnetic field and orient themselves during their journeys using this "biological compass." This reveals that they have an extraordinary ability to "see the invisible."

They also found that the protein in robins shows greater sensitivity to magnetism than that in chickens and non-migratory pigeons, further supporting its role as a magnetic sensor.

Xu, J., Jarocha, L.E., Zollitsch, T. et al. conducted the research entitled “Magnetic sensitivity of cryptochrome 4 from a migratory songbird”, published in the journal Nature in 2021.

This composition was made to participate in the Scientific Illustration contest of the Jot Down Magazine (2022).

Year: 2022
Technique: Digital illustration.
Illustration type: Naturalistic.
Type of project/Client: Personal.