I want to know the answer to the following question:
When did the ancestor of all modern birds evolve a better sense of smell?
All the background I'm provided with is that "While the earliest forms, such as Archaeopteryx and Jeholornis, retained the long bony tails of their ancestors, the tails of more advanced avialans were shortened with the advent of the pygostyle bone in the group Pygostylia.". Is that enough to answer the question?
Answer: no