September 13, 2007—The world of bird research lost one of its most charismatic ambassadors this week when Alex, a talking African gray parrot who was the subject of many studies, died at the age of 31.

Alex participated in many experiments that suggested he, and possibly other birds, could think and communicate at the level of a four- or five-year-old child. One study in 2005 even suggested that the parrot understood the concept of zero, a rarity in animals and even young humans.

See a 1999 television segment that shows Alex at work with Irene Pepperberg, a psychologist who worked with him for years and described Alex not as a pet or as a lab subject but as a colleague.