Cookie, the Major Mitchell’s cockatoo who’s been a celebrated part of Brookfield Zoo’s animal collection since the day the institution opened, died at the age of 83 on Aug. 27 after suffering what officials described as “an abrupt decline in his health.”

“This is a sad day for staff as well as for the many guests who came to Brookfield Zoo specifically to see Cookie,” said Stuart Strahl, president and CEO of the Chicago Zoological Society in a press release. “He was a charismatic animal and definitely had a loyal fan base. He will be greatly missed.”

Certified by the Guinness Book of World Records in 2014 as the oldest living parrot, Cookie came to Brookfield Zoo as the age of 1 from the Taronga Zoo in Australia and was on hand when the zoological park opened its doors in 1934.

Since then, he been a favorite of visitors and staff alike.

“I’ve been a basket case,” said Sondra Katzen, media relations manager for Brookfield Zoo, who would go visit Cookie periodically in the Reptiles and Birds staff office where he’s lived since 2009, when he “retired” from being on display.

“He was my favorite,” Katzen said. “He was such a special bird.”

Part of what made Cookie so engaging, said Tim Snyder, Brookfield’s Zoo’s curator of birds, was his ability to mimic and react to people. In the staff office where he lived, Cookie definitely played favorites, loudly squawking over people he didn’t like while gently chattering behind those he liked.

“He let you know who was boss,” Snyder said.

Snyder said that Cookie appeared to like people who wore glasses, and if he heard someone he liked talking in another room, Cookie would loudly repeat his name, “Cookie!” to get the person’s attention.

The zoo threw a birthday party for Cookie outside the Perching Bird House every year in late June, featuring a chorus of “Happy Birthday” from fans and a birthday muffin made from his favorite foods – carrots, raisins, apples, bananas and eggs – and topped with his absolute favorite, a green bean.

Throughout the years, Cookie provoked a strong reaction from admirers around the world. In 2008, a local artist named Mr. Nicky wrote a song in honor of Cookie’s 75th birthday. And in 2013, Dr. Sri Ganapathy Sachchidananda Swamiji, a holy man/healer who founded a parrot sanctuary in Mysore, India, made a special pilgrimage to Brookfield Zoo to see Cookie.

“He came with an entourage,” said Snyder. “It was quite the international affair.”

Also in 2013, the zoo began to dial back the birthday celebrations for Cookie, making the staff-only affairs, though the zoo would post videos of the events.

In recent years, Cookie suffered a variety of ailments, including cataracts and osteoarthritis, which was treated with a special diet, anti-inflammatory medication and vitamin supplements.

More recently, according to Snyder, Cookie was noticeably quieter and sleeping more. When the first staffer arrived in the office on Aug. 27, Cookie clearly was ailing and taken to the zoo’s hospital where the animal care staff made the “extremely difficult decision” to euthanize him.

According to Katzen, the Chicago Zoological Society is inviting people to post memories and condolences on the Brookfield Zoo Facebook page. Brookfield Zoo has also posted a video montage of Cookie on its Facebook page.

In addition, the society is setting up a memorial fund  for those who would like to make a donation in Cookie’s name. Contributions will go to the society’s Center for the Science of Animal Care and Welfare for the care, feeding and well-being of the zoo’s bird collection and other animals at the zoo.