Nice little video that mate
It's interesting as its very rare to see it growing on birch by me (and boy do we have a lot of birch around here) but it is very common on Oak and Beech here. Fungi can be a bit odd like that, I've only ever read of cramp balls growing on dead Ash but I've personally found it growing on dead birch quite happily, not commonly but I have found it
I've wondered about the carrying your fire with you idea ever since I saw it on a RM program years ago. I'm sort of with the thought that if you could use a bow drill or flint and iron pyritise effectively, and I'm guessing people could back then as a necessity rather than a hobby, then why would you waste fungi resources carrying it about? I don't doubt it was done but I'm just not sure how widespread or normal it was. Having said that I'm sure I read about a tribe somewhere who had lost the art of fire lighting as they had simply kept at least one fire burning since long before anybody could remember....like generations back.
Also, I'm no history or archeological whizz....so what do I know lol. It just doesn't seem to me something I'd do as a matter of course if I was a caveman.
Which sort of leads me onto why the heck I'd ever want to do it over here in modern times uk unless I was re-enacting something? I can see it might be useful to know but the only time I've ever used fungi this way was on a training course in Sweden a while back where we had to keep leaving the fire to go to lectures and didn't want to have to relight the fire every time we came back. Maybe that's reason enough to know about it.....maybe not
Thanks for posting the vid anyway
Cheers,
Bam.