What is the poem extract from out of blue about?

The poem "Out of the Blue" by Ruth Krauss is about a group of animals who experience a sudden change in their surroundings. The poem begins with the line, "Out of the blue, a bird flew," and goes on to describe how other animals, including a fish, a mouse, a cat, and a dog, react to this unexpected event. The poem's imagery and symbolism suggest that the animals are experiencing a moment of wonder and awe, and the poem's message is that even in the midst of ordinary life, there can be moments of magic and beauty.