The injuries to the beak and head are clearly visible
Four teenagers in Australia have been charged with an attack on an almost blind greater flamingo, thought to be one of the oldest of its kind alive.
Police and zoo officials said the flamingo's head and beak were injured and it was bleeding from an eye.
The bird, aged at least 75 years, is in a critical condition, zoo staff said.
The bird has been at the zoo for most of its life and, with its Chilean partner, has been one of Adelaide zoo's most popular exhibits.
Police said four men aged between 17 and 19 were charged with aggravated ill-treatment of an animal and released on bail to appear in court at a later date.
Several visitors at the zoo at the time of the attack had spoken about the incident with zoo staff and officers wanted to interview them, a spokesman said.
The injured bird, described as tame and docile, was sedated after the attack and taken to a local veterinary clinic where its condition was reported to have improved overnight.
The exact age of the flamingo remains unknown, as proper records from his arrival in the 1930s do not exist.
"The bird arrived at the zoo in 1933 and was a mature bird at that stage," a spokeswoman for the zoo told Agence France Presse.
"So although we don't know its exact age it is at least 75 years old - much older than they grow in the wild," the spokeswoman said.
"Although undoubtedly the oldest flamingo in the world its quality of life is very good," the zoo's website says.
Zoo bird keeper Vaughan Wilson was quoted as saying the birds had been popular partly because they were accessible to the public.
But he said the knee-high fence separating the flamingos from the crowd had always caused concern.
Australian newspapers reported that the attack had caused public outrage and that radio talk shows were overwhelmed by calls.
Adelaide zoo has had its share of brutal incidents before: in 1985, two men broke in and killed 64 animals.
In November 2006, a pair of valuable African grey parrots was stolen, seven months after the theft of a baby meerkat called Wanda.
A rare squirrel monkey was also taken in 2004.