trouble is when birds etc ingest cannabis seed ,Seeds can blow or be washed by spring floods into streams and rivers, and then to sea, to float to who knows where? Seeds are consumed by birds and some are emitted undigested from the birds onto lands. Pollen is much more mobile, as pollen could blow from a valley in Afghanistan, catch an updraft, and end up anywhere. A single bit of pollen is so light that if it got blown up into higher wind elevations, it could travel around the world.
its for one reason ,, to eat the embryo inside the shell ,
not likely any go through their digestion system and are still viable, if there was in fact the odd one to still be intact ,
i very much doubt any animals or birds spread cannabis seeds ,
its more likely done by an animal that used them for another purpose ,
like humans for instance .....
if birds were spreading cannabis seed , it would be on islands all over the world ,, that are not inhabited by man ,
and yet ...