Class Aves includes all birds, characterized by feathers, beaks, and the ability to lay eggs. Birds are warm-blooded vertebrates, meaning they can regulate their body temperature. They have lightweight skeletons that help them fly, although some species, like ostriches and penguins, are flightless. Birds are found in diverse habitats worldwide, from forests to deserts and oceans. They play essential roles in ecosystems, such as pollination and seed dispersal. With over 10,000 species, Aves exhibit a wide range of sizes, colors, and behaviors, making them a fascinating group of animals to study and observe.