Bird species are groups of birds that share common characteristics, such as physical traits, behaviors, and genetic makeup. There are approximately 10,000 different bird species worldwide, ranging from small hummingbirds to large ostriches. Each species has adapted to its environment, leading to diverse habitats, diets, and nesting behaviors. Bird species are classified into families and orders based on their similarities. For example, the Passeriformes order includes songbirds, while the Accipitridae family consists of birds of prey like eagles and hawks. Understanding bird species helps scientists study ecosystems and the impact of environmental changes on wildlife.