{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T01:04:36Z","timestamp":1789520676462,"version":"build-2803163510"},"reference-count":58,"publisher":"The Royal Society","issue":"242","license":[{"start":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T00:00:00Z","timestamp":1789516800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,9,16]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>A recent study (Nordmann et\u00a0al. 2025 Science\u00a0391, 1155\u20131160 (doi:10.1126\/science.aea6425)) proposes that magnetoreception in pigeons may arise from electromagnetic induction within the semicircular canals of the inner ear. In this framework, motion through the geomagnetic field is suggested to generate an induced electromotive force that leads to ion redistribution in the endolymph, activation of voltage-gated calcium channels and subsequent engagement of downstream neural circuits. In this work, I examine the physical plausibility of this mechanism using a toy model of the induction process combined with an information-theoretic analysis. I find that, under idealized assumptions, Faraday induction in the semicircular canals would not generate a signal of sufficient informational content to support the extraction of directional magnetic field information from the geomagnetic field. However, the model supports the possibility of inferences due to radio-frequency electromagnetic waves of a miniscule amplitude, thereby providing a potential rationalization of their disruptive effect on avian compass navigation.<\/jats:p>","DOI":"10.1098\/rsif.2026.0332","type":"journal-article","created":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T00:08:02Z","timestamp":1789517282000},"source":"Crossref","is-referenced-by-count":0,"title":["Signals too small to sense: physical and information-theoretic limits to induction-based magnetoreception in birds"],"prefix":"10.1098","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4236-2627","authenticated-orcid":false,"given":"Daniel R.","family":"Kattnig","sequence":"first","affiliation":[{"name":"Department of Physics and Astronomy, University of Exeter 1 , Exeter, UK"},{"name":"Living Systems Insitute, University of Exeter 2 , Exeter, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"175","published-online":{"date-parts":[[2026,9,16]]},"reference":[{"key":"2026091520075683200_RSIF20260332C1","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1038\/nrn1745","article-title":"The physics and neurobiology of magnetoreception","volume":"6","author":"Johnsen","year":"2005","journal-title":"Nat. Rev. Neurosci."},{"key":"2026091520075683200_RSIF20260332C2","doi-asserted-by":"crossref","first-page":"S273","DOI":"10.1098\/rsif.2009.0435.focus","article-title":"A quantitative assessment of torque-transducer models for magnetoreception","volume":"7","author":"Winklhofer","year":"2010","journal-title":"J. R. Soc. Interface"},{"key":"2026091520075683200_RSIF20260332C3","doi-asserted-by":"crossref","first-page":"20150499","DOI":"10.1098\/rsif.2015.0499","article-title":"Magnetic particle-mediated magnetoreception","volume":"12","author":"Shaw","year":"2015","journal-title":"J. R. Soc. Interface"},{"key":"2026091520075683200_RSIF20260332C4","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1146\/annurev-biophys-032116-094545","article-title":"The radical-pair mechanism of magnetoreception","volume":"45","author":"Hore","year":"2016","journal-title":"Annu. Rev. Biophys."},{"key":"2026091520075683200_RSIF20260332C5","doi-asserted-by":"crossref","first-page":"10823","DOI":"10.1038\/s41467-024-55124-x","article-title":"Magnetosensitivity of tightly bound radical pairs in cryptochrome is enabled by the quantum Zeno effect","volume":"15","author":"Denton","year":"2024","journal-title":"Nat. Commun."},{"key":"2026091520075683200_RSIF20260332C6","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/0022-5193(80)90217-9","article-title":"Magnetic induction for the sensing of magnetic fields by animals\u2014an analysis","volume":"87","author":"Jungerman","year":"1980","journal-title":"J. Theor. Biol."},{"key":"2026091520075683200_RSIF20260332C7","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1006\/jtbi.1995.0102","article-title":"Electroreception and the compass sense of sharks","volume":"174","author":"Paulin","year":"1995","journal-title":"J. Theor. Biol."},{"key":"2026091520075683200_RSIF20260332C8","doi-asserted-by":"crossref","DOI":"10.1016\/j.cub.2019.09.048","article-title":"A putative mechanism for magnetoreception by electromagnetic induction in the pigeon inner ear","volume":"29","author":"Nimpf","year":"2019","journal-title":"Curr. Biol."},{"key":"2026091520075683200_RSIF20260332C9","doi-asserted-by":"crossref","first-page":"1155","DOI":"10.1126\/science.aea6425","article-title":"A global screen for magnetically induced neuronal activity in the pigeon brain","volume":"391","author":"Nordmann","year":"2025","journal-title":"Science"},{"key":"2026091520075683200_RSIF20260332C10","volume-title":"The Feynman lectures on physics","author":"Feynman","year":"2006"},{"key":"2026091520075683200_RSIF20260332C11","doi-asserted-by":"crossref","first-page":"R1224","DOI":"10.1016\/j.cub.2019.10.022","article-title":"Magnetoreception: a dynamo in the inner ear of pigeons","volume":"29","author":"Winklhofer","year":"2019","journal-title":"Curr. Biol."},{"key":"2026091520075683200_RSIF20260332C12","article-title":"Specific gravity and viscosity of endolymph and perilymph","author":"Money","year":"1966"},{"key":"2026091520075683200_RSIF20260332C13","doi-asserted-by":"crossref","first-page":"409","DOI":"10.2187\/bss.15.409","article-title":"Cupula response and functional anatomy to pressure application in the pigeon","volume":"15","author":"Watanabe","year":"2001","journal-title":"Biol. Sci. Space"},{"key":"2026091520075683200_RSIF20260332C14","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1242\/jeb.55.2.371","article-title":"The electric sense of sharks and rays","volume":"55","author":"Kalmijn","year":"1971","journal-title":"J. Exp. Biol."},{"key":"2026091520075683200_RSIF20260332C15","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1126\/science.7134985","article-title":"Electric and magnetic field detection in elasmobranch fishes","volume":"218","author":"Kalmijn","year":"1982","journal-title":"Science"},{"key":"2026091520075683200_RSIF20260332C16","doi-asserted-by":"crossref","first-page":"418","DOI":"10.1016\/j.cub.2011.01.058","article-title":"Magnetoreception in an avian brain in part mediated by inner ear lagena","volume":"21","author":"Wu","year":"2011","journal-title":"Curr. Biol."},{"key":"2026091520075683200_RSIF20260332C17","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1038\/nature02534","article-title":"Resonance effects indicate a radical-pair mechanism for avian magnetic compass","volume":"429","author":"Ritz","year":"2004","journal-title":"Nature"},{"key":"2026091520075683200_RSIF20260332C18","doi-asserted-by":"crossref","first-page":"021506","DOI":"10.1103\/PhysRevE.70.021506","article-title":"Diffuse-charge dynamics in electrochemical systems","volume":"70","author":"Bazant","year":"2004","journal-title":"Phys. Rev. E"},{"key":"2026091520075683200_RSIF20260332C19","first-page":"5111","volume-title":"Handbook of chemistry and physics","author":"Van\u00fdsek","year":"1992"},{"key":"2026091520075683200_RSIF20260332C20","volume-title":"Electrolyte solutions","author":"Robinson","year":"2002","edition":"2nd rev. edn"},{"key":"2026091520075683200_RSIF20260332C21","doi-asserted-by":"crossref","first-page":"466","DOI":"10.1002\/ar.a.20304","article-title":"Semicircular canal geometry, afferent sensitivity, and animal behavior","volume":"288A","author":"Hullar","year":"2006","journal-title":"Anat. Rec. A"},{"key":"2026091520075683200_RSIF20260332C22","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1115\/1.2835073","article-title":"A poroelastic continuum model of the cupula partition and the response dynamics of the vestibular semicircular canal","volume":"121","author":"Damiano","year":"1999","journal-title":"J. Biomech. Eng."},{"key":"2026091520075683200_RSIF20260332C23","doi-asserted-by":"crossref","first-page":"239","DOI":"10.3109\/00016487709128840","article-title":"Electron probe determination of relative ion distribution in the inner ear","volume":"83","author":"Flock","year":"1977","journal-title":"Acta Otolaryngol."},{"key":"2026091520075683200_RSIF20260332C24","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1113\/jphysiol.1952.sp004695","article-title":"The microphonic activity of the lateral line","volume":"116","author":"Jielof","year":"1952","journal-title":"J. Physiol."},{"key":"2026091520075683200_RSIF20260332C25","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1007\/0-387-21567-0_4","volume-title":"The vestibular system","author":"Rabbitt","year":"2004"},{"key":"2026091520075683200_RSIF20260332C26","doi-asserted-by":"crossref","first-page":"716","DOI":"10.1021\/j150402a004","article-title":"The dielectric properties of the system gelatin-water. II","volume":"44","author":"Fricke","year":"1940","journal-title":"J. Phys. Chem."},{"key":"2026091520075683200_RSIF20260332C27","doi-asserted-by":"crossref","first-page":"jeb183475","DOI":"10.1242\/jeb.183475","article-title":"Head-mounted sensors reveal visual attention of free-flying homing pigeons","volume":"221","author":"Kano","year":"2018","journal-title":"J. Exp. Biol."},{"key":"2026091520075683200_RSIF20260332C28","first-page":"100490","article-title":"Nanoscale architecture and dynamics of CaV1.3 channel clusters in cardiac myocytes revealed by single channel nanoscopy","volume":"14","author":"Schwenzer","year":"2025","journal-title":"J. Mol. Cell. Cardiol. Plus"},{"key":"2026091520075683200_RSIF20260332C29","doi-asserted-by":"crossref","first-page":"2231","DOI":"10.1088\/0031-9155\/41\/11\/001","article-title":"The dielectric properties of biological tissues: I. Literature survey","volume":"41","author":"Gabriel","year":"1996","journal-title":"Phys. Med. Biol."},{"key":"2026091520075683200_RSIF20260332C30","doi-asserted-by":"crossref","first-page":"781","DOI":"10.1021\/j150393a011","article-title":"A dielectric study of the gelatin-water system: anomalous dispersion in bound (oriented) water","volume":"43","author":"Fricke","year":"1939","journal-title":"J. Phys. Chem."},{"key":"2026091520075683200_RSIF20260332C31","doi-asserted-by":"crossref","first-page":"8382","DOI":"10.1021\/ma980765f","article-title":"Solute diffusion within hydrogels. Mechanisms and models","volume":"31","author":"Amsden","year":"1998","journal-title":"Macromolecules"},{"key":"2026091520075683200_RSIF20260332C32","volume-title":"Electrochemical methods: fundamentals and applications","author":"Bard","year":"2001","edition":"2nd edn"},{"key":"2026091520075683200_RSIF20260332C33","doi-asserted-by":"crossref","first-page":"2664","DOI":"10.1016\/j.msec.2012.07.024","article-title":"Comparison of electrical conductivities of various brain phantom gels: developing a \u2018brain gel model\u2019","volume":"32","author":"Kandadai","year":"2012","journal-title":"Mater. Sci. Eng. C"},{"key":"2026091520075683200_RSIF20260332C34","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1085\/jgp.69.2.121","article-title":"Calcium-activated conductance in skate electroreceptors: current clamp experiments","volume":"69","author":"Clusin","year":"1977","journal-title":"J. Gen. Physiol."},{"key":"2026091520075683200_RSIF20260332C35","doi-asserted-by":"crossref","first-page":"818","DOI":"10.1097\/HP.0b013e3181f06c86","article-title":"Guidelines for limiting exposure to time-varying electric and magnetic fields (1\u00a0Hz to 100\u00a0kHz)","volume":"99","author":"International Commission on Non-Ionizing Radiation Protection","year":"2010","journal-title":"Health Phys."},{"key":"2026091520075683200_RSIF20260332C36","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1103\/PhysRev.32.97","article-title":"Thermal agitation of electricity in conductors","volume":"32","author":"Johnson","year":"1928","journal-title":"Phys. Rev."},{"key":"2026091520075683200_RSIF20260332C37","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1103\/PhysRev.32.110","article-title":"Thermal agitation of electric charge in conductors","volume":"32","author":"Nyquist","year":"1928","journal-title":"Phys. Rev."},{"key":"2026091520075683200_RSIF20260332C38","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1126\/science.2300806","article-title":"The response of living cells to very weak electric fields: the thermal noise limit","volume":"247","author":"Weaver","year":"1990","journal-title":"Science"},{"key":"2026091520075683200_RSIF20260332C39","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1103\/PhysRevA.43.1039","article-title":"Constraints on biological effects of weak extremely-low-frequency electromagnetic fields","volume":"43","author":"Adair","year":"1991","journal-title":"Phys. Rev. A"},{"key":"2026091520075683200_RSIF20260332C40","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1088\/0034-4885\/63\/3\/204","article-title":"Static and low-frequency magnetic field effects: health risks and therapies","volume":"63","author":"Adair","year":"2000","journal-title":"Rep. Prog. Phys."},{"key":"2026091520075683200_RSIF20260332C41","volume-title":"Information theory, inference, and learning algorithms","author":"MacKay","year":"2003"},{"key":"2026091520075683200_RSIF20260332C42","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1146\/annurev.bb.16.060187.002323","article-title":"Physical limits to sensation and perception","volume":"16","author":"Bialek","year":"1987","journal-title":"Annu. Rev. Biophys. Biophys. Chem."},{"key":"2026091520075683200_RSIF20260332C43","doi-asserted-by":"crossref","first-page":"2983","DOI":"10.1242\/jeb.032722","article-title":"A strong magnetic anomaly affects pigeon navigation","volume":"212","author":"Wiltschko","year":"2009","journal-title":"J. Exp. Biol."},{"key":"2026091520075683200_RSIF20260332C44","doi-asserted-by":"crossref","first-page":"1074","DOI":"10.1109\/10.855935","article-title":"Second-order lipid bilayer models of cell membrane electropermeabilization","volume":"47","author":"Kotnik","year":"2000","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"2026091520075683200_RSIF20260332C45","doi-asserted-by":"crossref","first-page":"3740","DOI":"10.1073\/pnas.92.9.3740","article-title":"Rectification and signal processing of weak electric fields by biological cells","volume":"92","author":"Astumian","year":"1995","journal-title":"Proc. Natl Acad. Sci. USA"},{"key":"2026091520075683200_RSIF20260332C46","doi-asserted-by":"crossref","first-page":"13488","DOI":"10.1038\/s41598-020-69561-3","article-title":"Non-thermal effects of radiofrequency electromagnetic fields","volume":"10","author":"Wust","year":"2020","journal-title":"Sci. Rep."},{"key":"2026091520075683200_RSIF20260332C47","doi-asserted-by":"crossref","first-page":"075201","DOI":"10.1088\/0957-4484\/21\/7\/075201","article-title":"Radio frequency rectification on membrane bound pores","volume":"21","author":"Ramachandran","year":"2010","journal-title":"Nanotechnology"},{"key":"2026091520075683200_RSIF20260332C48","doi-asserted-by":"crossref","first-page":"093105","DOI":"10.1063\/1.3626586","article-title":"Direct microwave transmission on single \u03b1-hemolysin pores","volume":"99","author":"Ramachandran","year":"2011","journal-title":"Appl. Phys. Lett."},{"key":"2026091520075683200_RSIF20260332C49","doi-asserted-by":"crossref","first-page":"093033","DOI":"10.1088\/1367-2630\/13\/9\/093033","article-title":"Radio-frequency response of single pores and artificial ion channels","volume":"13","author":"Kim","year":"2011","journal-title":"New J. Phys."},{"key":"2026091520075683200_RSIF20260332C50","doi-asserted-by":"crossref","first-page":"e17363","DOI":"10.1371\/journal.pone.0017363","article-title":"Monitoring voltage-dependent charge displacement of Shaker B-IR K+ ion channels using radio frequency interrogation","volume":"6","author":"Dharia","year":"2011","journal-title":"PLoS ONE"},{"key":"2026091520075683200_RSIF20260332C51","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1007\/BF01870471","article-title":"Radio-frequency rectification in electrogenic and nonelectrogenic cells of Chara and Nitella","volume":"65","author":"Barsoum","year":"1982","journal-title":"J. Membr. Biol."},{"key":"2026091520075683200_RSIF20260332C52","doi-asserted-by":"crossref","first-page":"596","DOI":"10.1097\/01.HP.0000257856.83294.3e","article-title":"A neurobiological basis for ELF guidelines","volume":"92","author":"Saunders","year":"2007","journal-title":"Health Phys."},{"key":"2026091520075683200_RSIF20260332C53","doi-asserted-by":"crossref","first-page":"483","DOI":"10.1097\/HP.0000000000001210","article-title":"Guidelines for limiting exposure to electromagnetic fields (100\u00a0kHz to 300\u00a0GHz)","volume":"118","author":"International Commission on Non-Ionizing Radiation Protection","year":"2020","journal-title":"Health Phys."},{"key":"2026091520075683200_RSIF20260332C54","doi-asserted-by":"crossref","first-page":"1475","DOI":"10.1016\/j.bpj.2017.07.031","article-title":"Disruption of magnetic compass orientation in migratory birds by radiofrequency electromagnetic fields","volume":"113","author":"Hiscock","year":"2017","journal-title":"Biophys. J."},{"key":"2026091520075683200_RSIF20260332C55","doi-asserted-by":"crossref","first-page":"e2301153120","DOI":"10.1073\/pnas.2301153120","article-title":"Upper bound for broadband radiofrequency field disruption of magnetic compass orientation in night-migratory songbirds","volume":"120","author":"Leberecht","year":"2023","journal-title":"Proc. Natl Acad. Sci. USA"},{"key":"2026091520075683200_RSIF20260332C56","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1038\/nature13334","article-title":"Sensory biology: radio waves zap the magnetic compass","volume":"509","author":"Kirschvink","year":"2014","journal-title":"Nature"},{"key":"2026091520075683200_RSIF20260332C57","doi-asserted-by":"crossref","first-page":"e17210","DOI":"10.7554\/eLife.17210","article-title":"Physical limits to magnetogenetics","volume":"5","author":"Meister","year":"2016","journal-title":"eLife"},{"key":"2026091520075683200_RSIF20260332C58","article-title":"Supplementary material from: Signals too small to sense: physical and information-theoretic limits to induction-based magnetoreception in birds","author":"Kattnig","year":"2026"}],"container-title":["Journal of the Royal Society Interface"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/royalsocietypublishing.org\/rsif\/article-pdf\/doi\/10.1098\/rsif.2026.0332\/6165738\/rsif.2026.0332.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/royalsocietypublishing.org\/rsif\/article-pdf\/doi\/10.1098\/rsif.2026.0332\/6165738\/rsif.2026.0332.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T00:08:09Z","timestamp":1789517289000},"score":1,"resource":{"primary":{"URL":"https:\/\/royalsocietypublishing.org\/rsif\/article\/23\/242\/20260332\/483289\/Signals-too-small-to-sense-physical-and"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,16]]},"references-count":58,"journal-issue":{"issue":"242","published-print":{"date-parts":[[2026,9,16]]}},"URL":"https:\/\/doi.org\/10.1098\/rsif.2026.0332","relation":{},"ISSN":["1742-5662"],"issn-type":[{"value":"1742-5662","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,16]]},"article-number":"20260332"}}