It is a stylistic device in which something ominous is signaled to happen in the future. Mama Milanoi experiences a pang of strange premonition that twists her nerves unpleasantly (p.17). This suggests the lurking danger especially because her daughters are in the status of intoiye nemengalana. Once they arrive in their new house, Resian says, "I feel an oppressive silence."(p.32).
This points at the rough episodes she encounters later (p.32). Taiyo and Resian experience a long night characterized by mournful calls of night birds (p.55). This signals the bad experience ahead. On page 138, Olmultut (a bird of bad omen) coos sorrowfully at Resian's gate. This bird is a harbinger of bad news. Its cry is ominous (p.138).