Most birds are warm-blooded vertebrates that belong to the class Aves. They have feathers, which are unique to this group, and most species are capable of flight. Birds typically have a beak, two wings, and lightweight bones, which help them soar through the air. They lay eggs, and their young often require care from their parents. Birds are found in diverse habitats around the world, from forests to deserts to wetlands. They play essential roles in ecosystems, such as pollination and seed dispersal. Common examples of birds include sparrows, eagles, and penguins, each adapted to their specific environments.