Veterinarians in New Zealand say a wayward emperor penguin, knicknamed Happy Feet, is in critical condition following two medical procedures performed at a zoo in Wellington.

On Friday veterinarians cleared the bird's throat. On Saturday they attempted to flush sand from its stomach. The bird had been eating sand and twigs on Peka Peka beach where it appeared earlier in the week, some 4,000 kilometers from its Antarctic homeland.

Emperor penguins eat snow to cool themselves, and zoo officials believe Happy Feet was trying to do the same with sand. They say they will try again Monday to remove remaining sand from the animal's digestive system.

Before it was taken to the zoo hospital, the bird attracted news crews and crowds of New Zealanders who wanted to see the rare visitor.

The last recorded sighting of an emperor penguin in New Zealand was 44 years ago. Emperors are the largest of the penguin species. Adults grow to more than a meter tall and weigh up to 30 kilograms.