Fossil birds are the preserved remains of ancient avian species that lived millions of years ago. These fossils provide valuable insights into the evolution of birds, showcasing their physical characteristics and behaviors. Many fossil birds are found in sedimentary rock formations, where conditions allowed for their preservation. The study of fossil birds helps scientists understand the transition from dinosaurs to modern birds. Notable examples include Archaeopteryx, often considered the first bird, which exhibits features of both birds and reptiles. Fossil evidence reveals how birds adapted to their environments over time, contributing to the diversity of species we see today.