The book contains no picture of Sigfrid, but the text describes her as a young woman with short, black hair. For the Bird Parade she is wearing a costume with black wings and an orange beak.
Twelve years before the events of the novel, when Sigfrid was 8, The Great Raven failed to show up for the annual Bird Parade (he had the bird flu), which left the people of Trolberg so depressed they neglected to work in the fields, resulting in a bad harvest and great hunger.
At the time the novel takes place, Sigfrid is president of TTC: Trolberg Trampolining Club. She is leading her club's float in that years parade, and like everyone else gets quite anxious when it seems the Great Raven won't show up again. Hilda meets Sigfrid when she tries to catch up with Trevor, who has taken the raven captive, by using her scarf and a telephone wire to make an improvised zipline, but falls off and lands on the TTC float. She lands right on top of the trampolines and thus unintentionally performs a quintuple backflip, which amazes everyone who sees it. Sigfrid helps Hilda down from the trampoline and ask the girl if she is okay. Hilda is fine and continues to chase after Trevor. Later, when the Great Raven has finally appeared and the parade is in full swing, Sigfrid notices Hilda in the crowd and gives her a happy wave as the TTC float goes past her.