Identification of male and female tiger heads: The male bird's face, chest and abdomen are yellow-green; the female bird's face is brown, the chest is gray with obvious vertical stripes, and the yellow hair on the head and cheeks is extremely sparse. Comparing the chin and chest, the male's yellow hair is abundant and conspicuous, but the female's is far different. Comparing the lower part of the lower back, the male has yellow color but the female does not.
In addition, goldfinch chicks can sing loudly and brightly when they separate male and female. The ones that are crisp and tactful are mostly male birds. You can also look at the belly shape. The male bird has a flat, short and wide abdomen, and the male bird has a protruding cloaca.