Scientists claimed to have taught a parrot to count items and identify objects and colours.
The grey parrot, called Alex, was cited as an example of how complex cognitive capacities existed in a wider range of animal species than previously thought.
According to Irene Pepperberg of Arizona University, Alex had learned to understand and use English labels to identify a range of objects, seven different colours (rose red, green, yellow, blue, grey, orange and purple) and various materials including paper, wood, rawhide and cork.
The parrot could identify, using a system of vocal labelling, 100 objects. Alex not only identified the objects but requested, refused and categorised them, said Dr Pepperberg. When distinguishing quantities of up to six objects he used the labels "two", "three", "four", "five" and "sih" (for six).
Dr Pepperberg said that Alex had used this ability for collections of novel objects, mixed sets of objects and sets in which the objects had been placed in random arrays.
Alex was also claimed to be able to categorise objects having both colour and shape when asked by researchers "what colour?" and "what shape?".
Dr Pepperberg said that the bird also "understood" concepts such as same and different; bigger and smaller as well as human phrases such as "come here", "I want X" and "I wanna go Y".