This years trip to Białowieża was in far less extreme weather conditions. Considering last year temperatures (below -20*C), this was almost a tropic with temperatures being around 0*C. I didn't have much luck with bison. We found early in the day 2 bulls feasting on the haystack, which is not very photogenic. Later that day we found two bigger herds and one of them was pretty far away and really not cooperative, started going away as we tried to approach it. The second one was more human-friendly. Most of the photos comes from the last encounter.
Still waiting for my shot of fighting bisons. Almost got one this time. ;)