Identification: birch eater

These big fungi are quite common on any decaying birches nearby... what are they?

Typical size about 10 cm in diameter, though some are much smaller.

 

Piptoporus betulina.

P.S. Great photos & description - please post here more!

 

Thanks for the ID! :-)

we've got plenty more fun(gi) lurking here in the south brunswick swamp, just have to find the time...