Crow is the common name for several species of black birds in the family Crowidae and genus Crow. Also known as Lao Lu, his mouth is filled with joyful cries. It is the largest bird in the Passeriformes order, with a body length of about 50 centimeters. The whole body or most of the feathers are blackish black, hence the name. Feathers are mostly black or black and white, with long beaks, some with distinct white collars, and black feathers with a purple blue metallic luster; Wings are much longer than tails; The mouth, legs, and feet are pure black. The distance between the nostrils and the forehead is about one-third of the length of the mouth, and the nose must be hard and straight, reaching the middle of the mouth.