Black Grouse lek in Bažu bog of Slitere National Park is the biggest in Europe. In 2009 there were counted 66 black grouse males together at one place. Landscape and strict protection of the area made it possible for this place to gain the status of Black Grouse capital.
Black Grouse mates in early spring. Males – cocks gather at their lek spots from wide area. Here they occupy their territory and protect it from the others. Boundary posts are small trees, grass clusters and small knolls. Most valuable territories are in the middle of the lek. As everyone tries to get as close as possible to the centre of the lek, territories of each cock there is smaller, but further away from the centre bigger. Males hiss, utter mating-calls, show off their splendid feathers and threaten each other with special warning call. And all this is because of humble females. When they show up, males become much more active to gain female attention as they are to choose male to mate with. Among all cocks only few of them will be the lucky ones. When fertilized, hens find a place to nest and care about chicks alone. Cocks continue lekking while hens start nesting. If first nesting fails, hen can go back to the lek and mate again.