YES, PARROTS ARE SENTIENT 

Ziggy is free-flying.  He has not had his wings clipped since he was in the original pet store 25 years ago.  My mother was a birder, and could never stand for wing clipping.  To that, I add my own brand of extremism: to me, a birdcage is a prison.

I had never thought about cages one way or the other until one day, shortly after I got him, when I realized just how intelligent he is. He was on my shoulder while I was walking around the kitchen trying to decide what to have for breakfast. I wasn't expecting an actual answer when I asked him, "What are we going to have for breakfast?" I did a double take when he replied, "Yum yum good egg." You cannot tell me that was mimicry: that was a specific answer to a specific question.  I have only heard him use that phrase once since.

It is unthinkable to imprison a sentient being like him. The only time he is caged now is when we are traveling or when there are visitors. (He is jealous, and won't allow anyone to get close to me.) I don't cage him when I'm gone: his room--which doubles as my bedroom--has thick plastic and other barriers to protect electrical outlets, etc.

Actually, my extremism goes further than just viewing cages as prisons:  I believe that all creatures are endowed by their creator with certain inalienable rights, and that the extent of those rights depends upon how sentient a particular creature is.

I am not using the term sentient in the philosophical sense or in the sense that animal rights advocates use it; I use it in what the Wikipedia article on sentience describes as the science fiction usage--it implies qualities such as "will, desire, consciousness, ethics, personality, intelligence, insight, and so on." Ziggy is not much of an animal rights advocate; he is perfectly willing (and happy) to eat his cousins (chickens, especially wing bones; he prefers drumstick bones, but I don't like the way drumstick bones splinter) and their unborn progeny (eggs). I, too, make no apologies for my biological heritage of being an omnivore, so please, PETA, no emails about the evils of eating meat.

The recognition of animal sentience is built into many laws, including that of the European Union, although the EU obviously uses the term in a more general sense than I do: 

In 1997 the concept of animal sentience was written into the basic law of the European Union. The legally-binding Protocol annexed to the Treaty of Amsterdam recognises that animals are ‘sentient beings’, and requires the EU and its Member States to ‘pay full regard to the welfare requirements of animals.’ [This quote appears verbatim in so many places, including Wikipedia, that I do not know to whom to give credit.]

Spain extends legal rights, including protection against being tortured or killed--and even exploitation for profit--to apes, but bullfighting remains legal, and they kill wild parrots in Barcelona. (Electric companies are still killing wild parrots in a number of American cities also.) I cannot fathom how anyone could kill or eat intelligent beings such as whales, gorillas, dolphins, or, most certainly, parrots.

Laws are more extreme in Switzerland.  The Swiss modified their constitution recently to make sure their citizens respect "the dignity of creation when handling animals, plants and other organisms." Their Federal Ethics Committee on Non-Human Biotechnology, concluded that "decapitation of wild flowers at the roadside without rational reason" is criminal--that it is impermissible morally to cause "arbitrary harm" to plants. Maybe there's a little bit of Buddhist in me because I have always been disgusted at people who would kill or destroy any life, including plants, for no reason, but the Swiss law strikes me as rather extreme.

Since Sept 1, 2008, even goldfish have been protected against physical and psychological abuse. Aquariums must allow fish to live in a natural day/night cycles. There are rigorous standards for how all social animals are treated. According to the Houston Chronicle, "the country's 160-page animal protection law states exactly how much space owners must give Mongolian gerbils (233 square inches) and what water temperature is required for African clawed frogs (18-22 degrees Celsius; 64-72 degrees Fahrenheit)." 

Switzerland's canton of Zurich requires that all animals have an attorney, and he is Mr. Antoine F. Goetschel.  But in a March, 2010, election, voters nationwide rejected a move that would have extended that requirement to the entire nation.