Threats to the yellow-eyed penguin/hoiho
Hoiho and chicks
Habitat destruction
Having a half and half existence - marine and land - hoiho need access to a private, scrub- or bush-covered area to breed and nest. Areas adjacent to the coastline that have been burnt or developed for farming or other forms of land development restrict their nesting options.
Yellow-eyed penguins are solitary creatures that seek privacy. Research has shown that the most intensively colonised areas, at around 16 pairs per hectare, are scrub-covered. A stark contrast to open forested areas where occupancy can be as low as .64 per hectare. For this reason a major tool for hoiho survival is replanting coastal sites with native shrubs and plants.
Predation
Yellow-eyed penguin adult at nest with
chick killed by a ferret, Otago peninsula
Chick predation is a major problem and for that reason pest control around nestijng sites is important. The main threats are from stoats and other mustelids, rats, cats and dogs. Dogs can also worry adult penguins and though they may survive an attack the stress caused in a colony can have a severe impact on chick health and survival. for this reason dogs are banned from entering penguin breeding areas.
Disease
As with all species disease is a threat to the hoiho's survival. In 2004 a new malady struck many of the mainland and Stewart Island populations. A diptheria-like disease, the corynebacterium infection killed 50 per cent of the the chicks in that season. It reappeared in only a few sites in 2005 and losses were minimal.
A new problem was identified during the 2005 season that affected chicks on Stewart Island. This is a blood borne protozoan parasite, leucocytozoon, that ends up in the liver. Malaria-like, it has a winged vector that's presumed to be black fly. This disease is host specific and occurs in over 60 species world wide. Two of them in New Zealand: a fich and the yellow-eyed penguin.
Human interference
In some readily accessible sites the popularlity of eco-tourism is having an effect on nest survival rates. One example shows that where there is extensive human interaction on a beach that adults need to cross to get to their nests and chicks, chick survival can be as low as 0.6. Whereas nearby colonies that aren't accessible have a survival rate of 1.7.
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