Short answers, pulled from the story.
Mozart purchased the starling on the 27th of May 1784 after hearing it sing a melody very close to the opening bars of the third movement of his Piano Concerto No. 17 in G, K. 453. He noted "That was beautiful!" in his expense book alongside a transcription of the tune. He likely taught the bird the melody himself, either in the pet store or wherever the purchase took place.
Mozart paid 34 Kreuzer for the starling, as recorded in his personal expense book on the 27th of May 1784.
Mozart's starling died on the 4th of June 1787, after three years as a pet. Mozart buried it in his hired garden with considerable ceremony, organizing a funeral procession of singers who were heavily veiled, composing a requiem, and placing a gravestone with a verse inscription.
Scholars West and King observed that many elements of Mozart's A Musical Joke, composed in 1787, bear what they describe as the vocal autograph of a starling. The starling also sang a version of Mozart's Piano Concerto No. 17 with small variations, including an incorrectly inserted fermata.
Mozart's family kept multiple birds, including a canary, tomtits, and a robin redbreast mentioned in a letter Nannerl Mozart wrote in 1775. At age 14, Mozart wrote from Naples asking after the family canary. In 1791, as Mozart lay dying, he was reluctant to have a pet canary moved away because he could no longer bear the sound of its singing.
Mozart composed a funeral poem for the starling that Robert Spaethling translated into English and described as humorous, bittersweet, and self-reflective. Biographer Franz Niemetschek, who interviewed Mozart's wife Constanze, confirmed that Mozart also gave the bird a proper gravestone with an inscription in his hired garden.