A homage to the final episode of the 1999 documentary series 'Walking With Dinosaurs'. The episode is titled 'Death of a Dynasty'.
As of writing this description, Walking With Dinosaurs is nearly 25 years old, and so some of the information provided by the narrator is either outdated or wrong. I have provided an example below...
The ecosystem of 'Death of a Dynasty' is primarly based of the Hell Creek Formation in the upper plains of the USA. This ancient habitat was not a volcanic ash wilderness, but a lush wetland. In fact, the planet itself didn't experience a 'massive surge in volcanic activity across the globe' at this time. There was a massive flood basalt, or 'large igneous province' in India 66 million years ago (the deccan traps), which may or may not have contributed to the dinosaur extinction event by releasing greenhouse gases and altering the climate. However, dinosaur and pterosaur fossils are abundant right up until the so called 'K-Pg boundary': a sharp geological line of iridium debrie - marking the impact of a large asteroid (not a comet as mentioned by the narrator) and the end of the age of dinosaurs. Most paleontologists would agree that the climatic after effects of this impact was the primary killer. The Hell Creek Formation is one of the best places in the world to study this mass extinction event.
Also, pterosaurs were not in decline and/or outcompeted into extinction by birds.