Flying in the north means that autumn has arrived. The reason why geese fly north: As soon as spring comes, the sunshine time in the north is prolonged, the trees grow vigorously and there are many insects, which is conducive to finding food and raising young geese. Goose's coming and going in spring and autumn are also related to endocrine glands in the body, such as pituitary gland and gonad, which secrete a stimulus to stimulate various parts of the body and produce reproductive requirements, so they fly to the north. The migration habit of goose family from south to north is also caused by historical reasons.