Courtesy of the freakonomics blog comes an article saying that monkey's also experience the uncanny valley effect. Original science daily is here, unfortunately without video.
A wonderful youtube video made the rounds recently of a chimpanzee's reaction to magic tricks. (may be more watchable with the sound down....)
It is interesting to see that the chimpanzee is often surprised and engaged by magic.
The interesting point of comparison is that children under 3 years old generally don't understand magic. At that age, their perceptions and expectations of how the world works are not well formed; not understanding the laws of physics, they aren't surprised when they are violated. This is well cited, an essay by Dave Kaye that talks about this.
Parrots can also detect magic. The charming book Becoming a Tiger: How Baby Animals Learn to Live in the Wild talks about the parrot Alex who would narrow his eyes tap his beak angrily on the table if his trainer did tricks with disappearing cashews (p320, since I went to the effort of looking it up :-) ).
From this, I'd conclude that chimpanzees and parrots have at least the intelligence level of a three year old child.
