I thought this was so sad, hearing about their last goodnight :(

WALTHAM, Massachusetts (AP) -- Alex, a parrot that 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.
Alex could count to six, identify colors and even express frustration with
repetitive scientific trials.

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.
Alex was discovered dead in his cage Friday, she said, 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
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 whether he was simply
mimicking researchers.

Alex hadn't reached his full cognitive potential and was demonstrating the
ability to take distinct sounds from words he knew and combine them to form
new words, Pepperberg said. Just last month, he pronounced the word "seven"
for the first time.

The last time Pepperberg saw Alex was Thursday, she said. They went through
their back-and-forth goodnight routine, which always varied slightly and in
which she told him it was time to go in the cage.

She recalls the bird said: "You be good. I love you." She responded, "I love
you, too." The bird said, "You'll be in tomorrow," and she responded, "Yes,
I'll be in tomorrow."