Waltham, Mass. ? Alex, a parrot who could count to six, identify colors and even express frustration with repetitive scientific trials, has died after 30 years of helping researchers better understand the avian brain.

The cause of Alex’s death was unknown. The African Grey parrot’s average life span is 50 years, Brandeis University scientist Irene Pepperberg said. She said Alex was discovered dead in his cage Friday but she waited to release the news until this week so grieving researchers could get over the shock and talk about it.

“It’s devastating to lose an individual you’ve worked with pretty much every day for 30 years,” Pepperberg told The Boston Globe. “Someone was working with him eight to 12 hours every day of his life.”

Alex’s advanced language and recognition skills revolutionized the understanding of the avian brain. After Pepperberg bought Alex from an animal shop in 1973, the parrot learned enough English to identify 50 different objects, seven colors, and five shapes. He could count up to six, including zero, was able to express desires, including his frustration with the repetitive research.

He also occasionally instructed two other parrots at the lab to “talk better” if they mumbled, though it wasn’t clear if he was simply mimicking researchers.