The foot of the boot is made of ostrich leg. I've not seen boots made of that before. The design is interesting and very classy looking when I dress up.
In fact, I liked these boots so much and they were so classy looking and comfortable, that I bought a pair just like them in brown, but identical in all other respects.
Here is how they look in the on-line catalog. My partner got them for me as a gift from Boot Barn.