Radical pair-based magnetic sensing in migratory birds

The navigational and sensory abilities of night-migratory songbirds, travelling alone over thousands of kilometres, are absolutely staggering. The successful completion of these magnificent voyages depends crucially on the birds’ ability to sense the Earth’s magnetic field. Exactly how this magnetic sense works is one of the most significant open questions in biology and biophysics. The experimental evidence suggests something extraordinary. The birds’ magnetic compass sensor seems to rely on coherent quantum phenomena that indirectly allow magnetic interactions a million times smaller than kBT (Boltzmann’s constant multiplied by temperature) to be detected in biological tissue. QuantumBirds brings together quantum physics, spin chemistry, behavioural biology, biochemistry, and molecular biology in a unique, ambitious, imaginative and genuinely synergetic research programme that will prove whether the primary magnetic detection event occurring in the birds’ retinas involves the quantum spin dynamics of photochemically formed radical pairs in cryptochrome proteins.We will address three specific questions:1. Are avian cryptochromes capable of functioning as magnetic compass receptors?2. Do retinal neurons encode light-dependent, cryptochrome-derived magnetic information?3. Are cryptochromes the primary magnetoreceptor molecules for magnetic compass orientation?Success in this endeavour will: (a) revolutionise our understanding of magnetoreception, the least understood of all biological senses; (b) firmly establish the emerging field of “Quantum Biology” and thereby reduce by six orders of magnitude the threshold for sensory detection of weak stimuli in biological systems; (c) prepare the ground for the development of a novel and powerful range of bio-inspired magnetic sensing devices; and (d) provide insights that could be applied in quantum computing and guide research into the potential effects of weak anthropogenic electromagnetic fields on human health.