The partial skeleton of a female gyrfalcon has been discovered near the top of a well in the citadel of Karabalgasun, the capital of the Uighur Empire (A.D. 745–840), in central Mongolia’s Orkhon Valley. Karabalgasun was destroyed and abandoned in A.D. 840, but the gyrfalcon’s remains have been radiocarbon dated to the eleventh or twelfth century, most likely during the reign of the nomadic Khitan or Liao Dynasty (A.D. 907–1125). Gyrfalcons, the largest species in the falcon family, appear naturally in Mongolia only on very rare occasions, but the fierce birds of prey were highly prized by Khitan leaders. According to ancient historical documents, they demanded white gyrfalcons as tribute from subjugated peoples living in the far north of their territory and used them to hunt swans as part of an annual spring ritual.

Several of the gyrfalcon’s rib bones show signs of healed fractures, injuries that would have doomed it in the wild. “This indicates that it was a captive bird that people cared for,” says Hendrik Rohland, an archaeologist working with the German Archaeological Institute. Along with the gyrfalcon’s remains, archaeologists have found burned animal bones that may be evidence of sacrificial rituals. “We see that the ruins of the city retained some significance for the people there,” says Rohland. “It was almost like a city of the dead, a place where you could deposit things and make sacrifices to the ancestors.”