Animals and plants possess internal clocks that attune them to the daily or solar as well as to the tidal or lunar rhythm on Earth. A key blue-light receptor serving for this purpose is a protein called cryptochrome. Another apparent role of cryptochrome is that of a sensor for the geomagnetic field. In this role cryptochrome assists migratory birds in long-range navigation (see February 2012, July 2010, July 2009, and April 2007 highlights). The magnetoreceptor function of cryptochrome arises from light-induced electron transfer between a flavin cofactor and a tryptophan residue. A recent study shows now that subsequent further electron transfers yield a pair of so-called entangled, freely to precess, electron spins spaced sufficiently far apart to establish cryptochrome's sensitivity to the geomagnetic field. The study reveals how, through a combination of classical motion of the protein and quantum dynamics of some of its electronic degrees of freedom the sequential electron transfer comes about and leads to the two widely separated electron spins. These spins act much like recently invented quantum computers, except that their role in migratory birds is to act as a light-driven magnetic compass. More on our cryptochrome webpage.