White-flippered penguins, korora, are found only in Canterbury and are a sub-species of little blue penguins.
The penguin colony at Flea Bay, near Akaroa, is the largest white-flippered penguin colony in mainland New Zealand.
In 2000, there were 717 breeding pairs in the bay. By the end of 2012, there were 1304, plus hundreds of juveniles and singles.
Department of Conservation ranger Anita Spencer credited predation work by the Department of Conservation, the Christchurch City Council and Environment Canterbury since 2001 for increasing the numbers.
However, it was the work done by local landowner and farmer Francis Helps during the past 20 years that had really helped, she said. Spencer said there were about 100 kill traps, which cost about $70 each, set around the bay which trapped predators, including stoats, ferrets and wild cats. The area had gone from strength to strength as lower levels of predation have greatly increased birds' chances of survival. "Other sea birds are instinctively realising it's a safe place to nest."
Three yellow-eyed penguin nests have been found in Flea Bay, which is the northern-most range for breeding for this rare penguin. Likewise, sooty shearwaters have also started nesting there. "It's just a really little slice of penguin paradise." Spencer said several of the penguins would return to breed there, but others would go further up the coast.
While the numbers were encouraging, it was important to continue protecting the rare birds, she said.