Why Do Parrots Parrot?

A lost parakeet in Japan was returned safely to its owner last week
after it told police its home address. Why do captive birds mimic
human speech, and how do they decide what to say?
 They’re trying to fit in with the flock, and they’ll say whatever it
takes. Parrots are among a handful of animal families that possess an
aptitude for vocal learning, meaning that they can form new sounds
based on experience.

In the wild, parrot flocks don’t talk like people, but they do seem
to develop distinct local dialects, and mated pairs may even sing
unique duets. This may allow them to keep untrustworthy newcomers
from joining their group…until the newcomer learns the language.
In one experiment, a group of parrots from one Costa Rican flock
was transplanted to a more northerly flock that showed different
vocalization patterns. About half flew right back home, but the rest
stayed and formed a sort of immigrant enclave with its own dialect.
One even learned the northern tongue and joined the locals.
 According to this theory, birds that are raised in captivity might mimic
their human owners as a way of gaining acceptance as a member of
the family. If they hear “pretty bird” a lot, they’ll interpret that as a
call distinct to their flock, and try making it themselves.
 Whether parrots can ever understand what they’re saying is still
debated. Researcher Irene Pepperberg trained an African Grey Parrot
named Alex some 100 human words, and the bird could identify
different objects by name. Skeptics have suggested that Alex’s abilities
might have been a product of the “Clever Hans” effect, in which an
animal gives correct responses based on its trainer’s body language.