Paleornithology is the scientific study of bird
evolution and fossil birds. It is a mix of
ornithology and
paleontology. Paleornithology began with the discovery
of
Archaeopteryx. The reptilian relationship of birds and
their ancestors, the theropod dinosaurs, are important
aspects of paleornithological research. Other areas of
interest to paleornithologists are the early sea-birds
Ichthyornis , Hesperornis, and others.