Natalie Angier in The New York Times:
Parrot partisans say the birds easily rival the great apes and dolphins in all-around braininess and resourcefulness, and may be the only animals apart from humans capable of dancing to the beat. “We call them feathered primates,” said Irene Pepperberg, who studies animal cognition at Harvard and is renowned for her research with Alex and other African grey parrots.
…Dr. Pepperberg and her collaborators have shown that African grey parrots have exceptional number skills: Alex could deduce the proper order of numbers up to 8, add three small numbers together and even had a zerolike concept — “skills equivalent to those of a four-and-a-half-year-old child,” Dr. Pepperberg said. Dr. Auersperg and her co-workers have found that Goffin’s cockatoos are more geared toward solving technical tasks. Alternately using their bills and feet, the birds can systematically make their way through a lock with five different complex mechanisms on it. Should they discover that one of the steps can be skipped en route to opening a chamber with a nut inside, they skip it the next time around. And in an act of ingenuity that Dr. Auersperg called “sensational” for an animal not known to use tools in the wild, a cockatoo named Figaro one day started carefully chipping at the edge of a larch wood frame until he had formed a long, slender pole, which he then wielded in his bill like a hockey stick to knock out pebbles and nuts hidden under boxes. “It took him 20 minutes to make his first tool,” Dr. Auersperg said. “After that, he could do it in less than five minutes.”