2. The meaning of this sentence is that the returning geese freed cattail and everything from the cold of winter, and cattail and everything ushered in spring, thriving and full of vitality.
The geese return after the vernal equinox, leaving the south where food is abundant and winter is warm, and finally come to the sunny and isolated Arctic geese in summer. Migrating geese, their chirping with wild poetry, brought poetry to the whole continent. The author thinks that goose is a very lovely animal, goose is a friend of human beings, and he likes goose.