In folk belief, the raven was associated with bloodshed, violence, and war. Its cry was rendered as “kro}, krou!” or “kryvi, kryvĭ!”, suggesting its connection with blood (Smolensk Province). Russian hunters even smeared raven’s blood on their gun barrels to improve their shooting accuracy. In a Polish legend from the Sieradz area, God turned a black raven into a raven as punishment for killing his brother. Bulgarians believed that noisy flocks of ravens foretold a village’s destruction by plague or an attack by the Turks (Marin.NV: 101).

— Gura. Animal Symbolism in Slavic Folk Tradition, p. 535