pepperberg

To demonstrate, Pepperberg carried Alex on her arm to a tall wooden perch in the middle of the room.

Not directly answering your question but related: Pepperberg and colleagues have done a fair amount of research into quantifying avian intelligence.

Irene Pepperberg studied an African grey parrot named Alex for 30 years.

Irene Pepperberg has had meaningful conversations with an African Grey parrot.

I worked in the Pepperberg lab as an undergrad back in the day, and he said that to me a hundred times too.

I worked in the Pepperberg lab as an undergrad.

Over the course of thirty years of work between psychologist Irene Pepperberg and Alex, purchased from a Chicago pet store at one year of age, the parrot amassed a vocabulary of some 150 words.

[...] [...] because Alex was able to produce a close approximation of the sounds of some English words, Pepperberg could ask him questions about a bird’s basic understanding of the world.

When he died in 2007, his last words to Pepperberg were reportedly "You be good.

For example "Irene Pepperberg’s work with Alex the parrot dwarfs the scientific contributions of all other sequencing to date put together." this is not true.

Pepperberg asked him, "What color three?" expecting him to say blue.

Without hesitation, Alex’s beak opened: “Co-lor.” “What’s different?” Pepperberg asked.

Irene Pepperberg's work with Alex the African grey parrot is to be believed, bird sapience has already been demonstrated.