  In a recent Letter [Phys. Rev. Lett. 109, 110502 (2012), arXiv:1204.6528],
Bandyopadhyay, Paterek and Kaszlikowski report their analysis of spin coherence
time in the radical pair involved in avian magnetoreception, concluding that is
of the order of a microsecond. However, a combination of an erroneous numerical
calculation together with an incorrect parameter drawn from an experimental
source have resulted in the authors underestimating by two orders of magnitude.
Consequently, one must reverse the authors' conclusion that the timescale is
consistent with experiments on cryptochrome.
