and... at the bottom of the page Stu links to, there is an even more amazing cladistic chart and other diagrams about the fossil records of birds and bird-like specimens.

I cannot imagine how anyone can see all that data and research without realizing how many millions of years it took to develop such an array. In the article they comment on the enormous number of missing links and other evidence, such as fossil nests (which are obviously hard to preserve) that would help produced even better charts. [Note: IF most specimens WERE available, there would not be enough paper to print the chart on!]