As everyone knows, parrots are remarkably good at mimicking human speech, but they tend to repeat randomly picked-up phrases: obscenities, election slogans, “Hey, sailor.” Many parrots kept as pets also imitate familiar sounds, like the family dog barking or an alarm clock beeping. But Pepperberg taught Alex referential speech—labels for objects, and phrases like “Wanna go back.” By the end, he knew about fifty words for objects. Pepperberg was never particularly interested in teaching Alex language for its own sake; rather, she was interested in what language could reveal about the workings of his mind. In learning to speak, Alex showed Pepperberg that he understood categories like same and different, bigger and smaller. He could count and recognize Arabic numerals up to six. He could identify objects by their color, shape (“three-corner,” “four-corner,” and so on, up to “six-corner”), and material: when Pepperberg held up, say, a pompom or a wooden block, he could answer “Wool” or “Wood,” correctly, about eighty per cent of the time. Holding up a yellow key and a green key of the same size, Pepperberg might ask Alex to identify a difference between them, and he’d say, “Color.” When she held up two keys and asked, “Which is bigger?,” he could identify the larger one by naming its color. Looking at a collection of objects that he hadn’t seen before, Alex could reliably answer a two-tiered question like “How many blue blocks?”—a tricky task for toddlers. He even seemed to develop an understanding of absence, something akin to the concept of zero. If asked what the difference was between two identical blue keys, Alex learned to reply, “None.” (He pronounced it “nuh.”)It's difficult to know exactly what level of awareness Alex the parrot would have of his own abilities--though, to be fair, two-year-old humans, with rare exceptions, aren't terribly reflective. Regardless, that Alex could endure the training of ethologists like Pepperberg shows either a remarkable patience or a stultifying lack of drive, seen usually in nearly-graduated seniors.
I should also add that I don't really think of admitting animal intelligence as knocking humans off a pedestal; as I've written time and again, it's more a matter of raising others closer to our humble perch.
For examples of other non-human leaps toward human heights, see this NewScientist summary.