[kaiwen1]

Upvote for the mockingbird. One fellow has for years perched himself in tree near the sidewalk tables at my favorite restaurant. His songs are as good as the food.

> only three species of birds survived the Chicxulub asteroid impact

I think it was three clades that survived, not individual species.

[moultano]

Yes, it's possible that some of the diversification within those clades happened before the impact, but the start of the radiation is so close to the impact that I think it's unlikely that it happened earlier. It would be too much of a coincidence, and the error bars for the molecular clocks almost always include the impact.