Sirin and Alkonost. Birds of joy and sorrow by Viktor Vasnetsov, 1896
Alkonost and Sirin are creatures from Slavic folklore. Alongside with Gamayun, another bird-maiden, they play a significant role in Russian mythos. Their main duty is to ward the Tree of Life. They’re commonly believed to be a fusion of Greek legends, Pagan Slavic folk tales and Christian lore.
Sirin was initially based on Greek sirens, with possible addition of traits characteristic of Slavic water spirits, in particular that of wila. However, she later assumed more positive features, becoming a symbol of harmony, joy and beauty. Sirin descends into world of mortals, singing of incoming happiness. Even in later legends her voice is enticing to the point of being dangerous to humans and Siren can be associated with treachery, insanity and temptation. As bird-maiden is sensitive to loud noises, people would save themselves from her hypnotic song by ringing bells and shooting cannons.
Alkonost is possibly named after Alcyone, a Greek demigoddess transformed into a kingfisher. Her voice possess the same bewitching capacity as that of her sister. Alkonost is typically associated with Hors, the god of sun. Sometimes called the bird of dawn, she brings winds and lightnings on her wings. It is believed that on Koliada (a holiday in the middle of winter) Alkonost lays eggs on the seashore. For seven days after that sets good weather.