I could have sworn I remember hearing this a few years back & that it was discovered due to the increase in shifting of magnetic north over time, & that their m

I could have sworn I remember hearing this a few years back & that it was discovered due to the increase in shifting of magnetic north over time, & that their migrations back home correlated in that they were off by that amount.. At least that's what I've been telling folk. NewScientist I'm certain.