This little article describes a fossil find that demonstrates a transition state between dinosaurs and birds. Critics of evolution often suggest that the fossil record is incomplete and has missing links. This is a bogus argument, however, because the fossil record is expected to be incomplete, not because of any shortcoming of evolution, but for geologic reasons. Fossils only form when an animal is quickly buried in something that excludes the usual chemicals that promote tissue degeneration. The majority of animals and plants that have lived have died in mundane ways that do not lead to fossils.
More significant is the strong evolutionary trends that can be seen in the fossils we have found. The dinosaur to bird transition is just one. New fossils are being unearthed every day and over the centuries that fossils have been collected and studied, nothing in the millions of fossils strongly contradicts the theory of evolution.