A very interesting study and I don't know if I agree 100% with the results because i think it can also go exactly the other way (meaning, the birds were better at adapting to begin with and that's why they ended up eating from humans) - not on pet or even wild parrots but can this be applied to our undomesticated species made into pets?
https://www.nature.com/articles/s41598-020-66165-9