(CNN) -- An emperor penguin that lost its way from Antarctica more than two months ago was released back into his native Southern Ocean waters Sunday.
"It's an indescribable feeling to see a patient finally set free," said Dr. Lisa Argilla, manager of veterinary science at Wellington Zoo, where the bird has been recuperating since New Zealanders discovered it in June on a beach north of the capital city.
Argilla said the penguin, nicknamed "Happy Feet" after the 2006 animated movie about emperor penguins, needed "some gentle encouragement" to slide down a ramp off the research vessel that transported it back home.
"But once he hit the water he spared no time in diving off away from the boat and all those 'aliens' who have been looking after him for so long," Argilla said in a statement posted on the zoo's website.
It's unclear why the penguin apparently swam more than 3,000 kilometers (1,864 miles) from Antarctica. Argilla said in June that the bird might have gotten lost in a current, or perhaps its internal radar went awry.
The bird was found "exhausted and hungry" on Peka Peka beach on New Zealand's Kapiti Coast this summer, according to the zoo. It underwent multiple stomach flushes and an endoscopy at the zoo to rid its stomach of sand it ingested while trying to adapt to the foreign environment.
"In Antarctica, they normally eat ice to cool down and to hydrate," Kate Baker, a spokeswoman for the zoo, said in June. It's possible the bird mistook or tried to substitute the sand for snow or ice, she said.
The penguin left the zoo Monday and spent the past six days on the research vessel in a specially designed crate stocked with ice.
A satellite tracker and microchip will now allow fans of the bird to follow his adventures in Antarctica at www.nzemperor.com.