What does «heteromancia» mean in Spanish?

Superstitious divination made by the flight from one side to the other of birds. Also known as ornithomancy (this includes their songs and appearances in general). It had its peak during the Middle Ages.

Examples of use in Spanish: "También practicaban la quiromancia, la cartomancia, la heteromancia y en casos extremos hasta la nigromancia", Dioses, semidioses y astronautas: novela, Nicolás Kingman - 1982

"no se queda mirando el revoloteo de los pájaros como un heteromántico pensativo: Zeno no es un ser aéreo dedicado supersticiosamente a la heteromancia", Davar - 1969