Viktor Vasnetsov’s Sirin and Alkonost  Birds of Joy and Sorrow (1896) courtesy of the Russian Museum 

The Alkonost is, according to Russian mythos and folklore, a creature with the body of a bird but the head of a beautiful woman. It makes sounds that are amazingly beautiful, and those who hear these sounds forget everything they know and want nothing more ever again. She lives in the underworld with her counterpart the sirin. The alkonost lays her eggs on a beach and then rolls them into the sea. When the alkonost’s eggs hatch, a thunderstorm sets in and the sea becomes so rough that it is untraveled. 

via