Erratum to: Hypothetical superparamagnetic magnetometer in a pigeon’s upper beak probably does not work Petr Jandačka, Petr Alexa, Jaromır Pištora and Jana Trojková Eur. Phys. J. E, 36 8 (2013) 96 Published online: 30 August 2013 DOI: 10.1140/epje/i2013-13096-9