This is the first video I have watched of his.

Claim 1 - Scientists researching the mice there, that were already suspected to be brought to the Azores from Europe found they were most closely related to mice from Scandinavia.

Claim 2 - Core samples keep finding spores they shouldn't find at all in stratum that predates the Portuguese. Including evidence of northern crops and mushrooms one might expect to find if northern europeans were farming the land

Interesting claims. None of his own research and he doesn't say its proven just head scratching.