What is a bird ab

The bird is popular in western ancient divination method."Sui, book biography of the western regions and the records about bird bligh:" I wish the offerings, into the mountain, there is a bird like hen pheasant, palm, to set broken its abdomen and, millet is years, sand is a disaster, "bird bligh."Means ancient western people often after the sacrifice to the mountain to pray, then there will be a bird fly, people catch a bird, open abdomen to see whether there is food in the stomach, if there is food, means that the next year was a bumper year, internal is empty, if the bird is the natural disasters affect the harvest.