Local penguin mortality recorded in New Zealand | Polarjournal
In New Zealand, the rare yellow-eyed penguins breed. Only about 4’000 animals of this species are said to exist worldwide. Due to introduced animal species such as cats, rats and other bird species, the animals that dwell in burrows are threatened. Because besides plundering the nests, foreign species can also introduce diseases against which the penguins have no chance. Picture: Michael Wenger

More than half of all 18 known penguin species do not live directly in Antarctica, but further north. New Zealand in particular is a real hotspot, with nine species breeding on New Zealand-administered land and another three in New Zealand itself. However, these three are among the rarer species and the state is undertaking great efforts accordingly to ensure their protection. But now the authorities are sounding the alarm: an increase in chick mortality and a decrease in the number of nests have been recorded among the yellow-eyed and little penguins. Despite investigations, the reasons for this remain unknown.

In the southeast of New Zealand’s South Island, in the Otago region, authorities had recorded 30 dead yellow-eyed penguin chicks in January this year in the area around the city of Dunedin alone, much higher than the average. An examination of the dead animals showed that they died of a pneumonia-like illness. However, no pathogens could be detected, as reported by the authorities and the media. “At this stage we do not know what caused the lung syndrome,” the head of Dunedin Wildlife Hospital Trust tells media platform Stuff. The chicks were examined in this veterinary facility. What is clear at present is that only chicks weighing less than one kilo are affected by the disease. Once over this critical weight or age limit, they are out of danger. But since it is not clear how many chicks have survived the disease, how and whether it can be transmitted from adults, and how affected animals can be treated, experts expect the worst.

Yellow-eyed penguins are divided into two subpopulations: the northern one in New Zealand and Stewart Island, and the southern one on sub-Antarctic islands such as Enderby and Campbell. While the southern population appears to be stable, the northern population has shrunk between 65 and 76 percent. Overall, this species is one of the rarest penguins in the world. Picture: Michael Wenger

For the Nature Conservancy of New Zealand, the loss of 30 chicks is a major setback in conservation efforts. This is because the number of yellow-eyed penguins in New Zealand has been in massive decline for years, between 65 and 76 percent in the last 20 years, according to the IUCN Red List and the conservation authority Te Papa Atawhai. While 177 breeding pairs are still known on the South Island, there were just 39 on Stewart Island. For comparison: A census in 2008 found 158 breeding pairs at that time. In contrast, the population on the subantarctic islands of New Zealand, for example Enderby or Campbell, seems to be stable. Reasons for the massive loss in the New Zealand heartland could include introduced predators such as cats and dogs, human disturbance in breeding areas and increased coastal fishing. But also pathogens are not excluded. A new plan unveiled last August was supposed to help numbers rebound.

Declines in yellow-eyed penguins have been reported in the Otago region, while those of little penguins have been reported near Christchurch. However, while little penguins are found in other parts of New Zealand and Australia, yellow-eyed penguins are restricted to the south and east sides of New Zealand’s South Island and a few subantarctic islands. Image: Michael Wenger via Google Earth

Further north from Otago and the yellow-eyed penguins, a decline in another popular penguin species is also being reported. A provider for observations of white-winged little penguins, found only on the Banks Peninsula near Christchurch, reported an eventual big drop in population numbers. At some breeding colonies, the number has dropped by up to 50 percent within four years, New Zealand media write. An initial survey in the region found 81 colonies by the start of the breeding season. From here on the counting had to be stopped so that the animals could breed undisturbed. But a last count 20 years ago had listed 174 colonies. The owner of an eco-company that does observations and monitoring of the little penguin species said that while this year has been good for chick numbers. But in some places the chicks in the nest boxes that were set up were very thin and underweight. This could be an indication of the decline in recent years. Because the little penguins are searching for food in the same regions as the fishermen with their trawl nets. But their vulnerability to disturbance during the breeding season could also be a reason. Te Papa Atawhai cites this year’s La Niña phenomenonas another reason, with warmer water upsetting the food web.

Little penguins are at home in Australia and New Zealand. But in the Christchurch region there is a separate population of a morph that belongs to the same species, but looks different: The white-winged little penguin. As the animals are highly endangered on the mainland, especially during the breeding and moulting season, boxes have been erected for their protection. Image: Kimberley Collins, Wikimedia CC BY-SA 4.0

The little penguins in New Zealand mostly live now on the offshore islands in the south of the country. On the mainland, the main threats to the penguins, which are only 30 centimetres tall, are cats and dogs plus disturbance from visitors to the beaches. To get a better overview of the populations, the authorities have cordoned off many areas during the breeding season, set up breeding and moulting boxes and also used cameras for observation. The little penguins come ashore from the sea mainly at night to feed the young and go back out to sea before dawn. There, however, they increasingly come into conflict with the fishing industry. It is estimated that half a million adults are still alive worldwide. But already just under a third of all populations are in decline, including in New Zealand. Hopefully, New Zealand’s featured plan will help these feisty little birds to recover. Because penguins are very popular in New Zealand. This year Heritage Expeditions was the only company to offer trips to virtually all of New Zealand’s penguin species (except Antarctica) to the local public, and interest was correspondingly high.

Dr Michael Wenger, PolarJournal

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