Birds are the floorboard of animals, namely Jinjiao, Kanghuolong, Nyctereute, Fangmu Rabbit, Heartfire Fox, Tailwater Tiger, Keppel Leopard and Kirin. Therefore, birds that miss birds for twenty-eight nights are the floorboard of animals.
Twenty-eight constellations were divided by ancient astronomers in China to observe the movements of the sun, the moon and the five stars. They are composed of seven constellations: Oriental Dragon, Southern Suzaku, Western White Tiger and Northern Xuanwu. For the record, the answer is for reference only. Please don't be blind and superstitious.