This computational model doesn't match the fossil record which suggests the flaw is in the model, not the evidence.
> Jacob Berv, an evolutionary biologist at the University of Michigan who was not involved in the study, said that it illustrated state-of-the-art methods for crunching huge amounts of genetic data to reconstruct evolutionary history. But he did not agree with its conclusion.
> If the new study was right, there should be fossils of all major groups of living birds from well before the asteroid impact. But almost none have been found.
> “The signal from the fossil record is not ambiguous,” Dr. Berv said.
> Dr. Berv suspects that the correct story comes from the fossils, and that most major groups of birds emerged after the asteroid impact. The potential problem with the new study, he said, is that it assumes that the bird DNA accumulated mutations at a steady rate from one generation to the next.