Birds in general and parrots in particular are usually considered symbols of spying and transmitting information. There are some English idioms referring to birds, such as "A little birdy told me so", or "I'm watching you like a hawk." We've all heard these in movies for sure.
But this symbol of surveillance associated to birds has been used by numerous cultures, since Biblical times if we consider the Book of Ecclesiastes 10:20: "Do not revile the king even in your thoughts, or curse the rich in your bedroom, because a bird of the air may carry your words, and a bird on the wing may report what you say."
In popular culture, parrots have been largely used as storytellers. In most stories, parrots were used to reveal secrets about certain characters. Parrots' use as revealers of secrets was widely spread in the Far East.
There was such a story in China, referring to a talking parrot that warned a man who was deceived by his wife. In fact, the parrot was used there as a warning symbol for women to make them be faithful towards their husbands.
There is a legend of a pearl merchant living in the Kiangsi province, who was almost ruined by his unfaithful wife and her malicious intrigues. A parrot warned this man about his wife's unfaithfulness, and thus his misfortune was avoided.
There is a book entitled "Understanding Surveillance Technologies" which has a chapter dedicated to spying animals. Apparently, animals have been used as surveillance methods because they are very cooperative, some of them can fly, they have more acute senses than humans, and so on.
Carrier pigeons are generally associated with the image of carrying romantic messages between two lovers. But the reality is, they had a more sinister usage as well.
Apparently, hundreds of thousands of carrier pigeons have been used, and no less than 95% completed their missions successfully. But their use as spies did not end with the 2nd world war; it was continued all throughout the 1950s.
Thus, carrier pigeons outdid themselves in their service for humans - they were used not only for carrying out messages, but also for performing an unusual task, that of photographing for the governments of different countries.
At any rate, this humanly impulse of spying on other people and especially of listening to other people's conversations, is older than the times when the telegraph and telephone appeared. In fact, the parrot became a very popular house pet in the 18th century because of its well-known capacities to remember people's conversations and to render them later on.
However, until the 19th century, parrots were not bred on the European continent; they were brought from Africa or South America. They were the second most popular exotic pets after canaries. Parrots' most advertised and appreciated quality was of course, their "power of speech."
They were considered to be surprisingly just and honest animals and their qualities made them both funny and useful pets for many people who either wanted to impress their family and friends, or to fulfill their desire of spying on others.
Many parrot poems and anecdotes appeared, which used the mimicry of the parrot as a hilarious way of cutting through facades and revealing usually hidden or forbidden political and social truths.