The Bird Lover

The Bird Lover, also known as The Prince as Bird, is a type of narrative structure in folklore, no. 432 in the Aarne–Thompson classification system. In the typical version of story, a woman acquires a bird lover—a nobleman in the shape of a bird—who is wounded by means of a trap set by the woman's husband, such as a set of sharp points set up outside the woman's window. She follows the wounded bird's trail, cures him, and then marries him.
In French scholarship, this type is often referred to as "loiseau bleu" or "the blue bird", so named for a story by Madame d'Aulnoy.
Origins.
Professor Jack Haney traced the origins of the tale type to France and Germany in the Middle Ages.
An example of the motif is found in one of Marie de France's "Lais", "Yonec", though the lai develops somewhat differently: instead of a happy ending, the lai ends in tragedy. A "sophisticated rationalization" of the type is found in Chrétien de Troyes's "Lancelot, the Knight of the Cart", where Lancelot appears at Guinevere's heavily barred window and cuts his fingers bending the bars back.
Variants.
Scholar Jack Haney stated the tale type enjoyed "worldwide distribution".
The ATU 432 folktype is also present in the folklore of Latin America, for instance, in Chile ("The Parrot Prince").
Professor Christian Abry stated that the tale type is "frequent" ("fréquent") in Italy.
Folklorists Wolfram Eberhard and Peterv Boratav listed 31 variants of the tale type in Turkish sources.