The yellow-eyed penguin is quietly losing its battle for survival in a land where paradise was lost with the arrival of people.
The Emperor penguin is arguably the most familiar penguin in the world, the poster penguin for climate change as global warming melts Antarctic ice. Films such as March with the Penguins document this magnificent penguin’s survival in such an inhospitable environment.
But not all penguins live in sub-zero temperatures. Some endure challenging environments higher up the temperature scale, but their battle for survival goes almost unnoticed despite being an ‘Endangered’ IUCN Red List Threatened Species.
Native and endemic to New Zealand, the yellow-eyed penguin is immortalised on the nation’s five dollar note, yet sadly it’s one of the rarest penguins in the world. Experts believe the species is the oldest of seventeen penguin species living today. It’s also unique as penguins go, not only for its solitary behaviour, but also for its forest habits.
Yellow-eyed penguin forest habitat
The yellow-eyed penguin (Megadyptes antipodes) breeds on the southeast coast of the South Island and southern offshore islands. The breeding sites used by yellow-eyed penguins today were once coastal hardwood forests.
Millions of years ago, these gentle, solitary penguins enjoyed the cool protective sanctuary of a forest canopy that stretched the length of South Island’s east coast. To survive the icy sea, penguins are insulated by fat, but on land the yellow-eyed penguin needs protection from New Zealand’s tropical heat and storms. The forest provided plenty of weatherproof nest sites, as well as protection for chicks against seabird attacks. With no other predators to steal eggs and chicks, New Zealand’s forests were abundant with birds. The ground dwelling kiwi and kakapo, the latter now critically endangered, flourished alongside the yellow-eyed penguin in a forested paradise.
Maori and European arrival destroyed coastal forests
This peaceful existence changed with human invasion, first by Maori then Europeans. They brought rats, dogs, cats and mustelids, and burnt coastal forests to create settlements and farmland, destroying bird life and habitat, and changing the landscape dramatically.
Penguins were forced to nest further inland, and adults, eggs and chicks became easy prey for cats and dogs, as well as for stoats, brought to control the soaring rabbit populations European settlers had created.
Conservation groups restore habitat
The Department of Conservation (DoC), the Yellow eyed Penguin Trust, Forest and Bird, Penguin Place, Penguin Rescue, scientists, community groups and private landowners are collaborating to save the yellow-eyed penguin. Conservation work includes restoring coastal forest and scrub, fencing off nesting sites from livestock, providing nesting boxes, controlling predators, and treating sick and injured birds. But like the yellow-eyed penguin’s return journey from sea to nest, it’s an uphill struggle fraught with setbacks.
Sharp decline in yellow-eyed penguin breeding pairs
The Department of Conservation (DoC) has reported a sharp decline in penguin nesting numbers counted in South Island’s Otago and Southland regions, down from 491 breeding pairs in 2012 to around 160 counted by the end of 2015, with the final total not expected to exceed 190 breeding pairs.
Yellow-Eyed Penguin Trust General Manager Sue Murray is concerned that repeated poor breeding seasons have major management implications. Conservation group staff and volunteers are exceptionally busy during spring and summer months, regularly checking beaches for distressed birds, as well as monitoring nest sites.
Populations have suffered devastating events over the last few years, including:
- unexplained deaths thought to be caused by a toxic marine-based pollutant
- widespread starvation in adults, juveniles and chicks
- avian diphtheria in chicks
- higher incidence of barracouta attacks
In early 2013, a mass mortality event thought to be a marine bio toxin claimed the lives of over 70 adult and juvenile penguins on the Otago Peninsula.
Later that year, many chicks starved early in the breeding season and those who survived had severely reduced chances of surviving at sea. By early 2014, many juveniles and adults needed supplementary feeding with fish, supplied by local fisheries, to help them fatten up ready for their moult.
Then an outbreak of avian diphtheria struck later in 2014. The disease causes mouth ulcers that severely restrict feeding and breathing. DoC and conservation groups provide treatment and supplementary feeding to reduce chick mortality. Even before avian diphtheria joined the list of threats, only 19 percent of chicks fledged. Juvenile penguins are now a rare sighting.
In the first four months of 2015, more than 55 adult penguins were injured, most likely from attacks by barracouta as they compete with penguins for food.
Habitat loss leaves adults and chicks vulnerable
Yellow-eyed penguin mating pairs build a nest of twigs, grass and leaves in patches of forest or dense vegetation where they can find a hollow secluded from other penguin nests. Two eggs are usually laid within a few days of each other and parents share incubation, chick guarding and feeding.
As well as avian diphtheria, chicks fall victim to heat stress, human disturbance, trampling by livestock, and predation by feral cats, dogs, ferrets and stoats. Parents are ill-equipped to fight off these vicious non-native predators. When chicks are six weeks old, they are left alone while both parents go to sea in search of food. Yellow-eyed penguin chicks don’t have the safety in numbers that penguins living in colonies can rely on.
Adult penguins are at risk of dog attacks during their long trek from sea to nest, which involves crossing open pasture. With inadequate forest protection, penguins are also vulnerable to heat stress when on land, which accounts for more than half the time for adult penguins. At sea, yellow-eyed penguins are preyed on by sea lions, fur seals and sharks.
The death of a parent in the post guard stage means one chick will die. A single parent cannot feed two chicks until they are ready to feed themselves, which is not until four months of age.
Impact of commercial and recreational fishing
Penguins are also at risk from non-targeted fishing methods such as gill nets, which entangle and drown them. Conservation groups are calling for an extension to the set net ban zone, out to the 25 km mark, the extent of the penguin’s feeding range. Such a ban would also benefit Maui and Hector’s dolphins, New Zealand fur seals and diving seabirds, but a powerful fishing lobby has so far prevented any extension.
Yellow-eyed penguins feed mainly on squid, as well as sprat, red cod, opal fish, silversides and blue cod, although there is no firm evidence that fisheries directly affect feeding opportunities. Reduced food supply impacts adult health, breeding, chick rearing, fledging weights and chick survival.
Easy to recognise but difficult to see
Around 60 cm tall, the yellow-eyed penguin takes its common name from pale yellow eyes, unique to this species. Its Maori name is hoiho, or ‘noise shouter’ because of its unmistakable range of calls and trills. With white chest and belly, slate blue back and tail, pink feet, and a distinctive yellow band crowning its head, the yellow-eyed penguin is easily identifiable. But you’ll have to be eagle-eyed and quiet as a mouse. These penguins are rare and if you do spot one, these shy birds don’t respond well to human disturbance, so you could unknowingly affect breeding and chick-rearing behaviour.
Impact of human disturbance
Penguin Rescue, a rehabilitation centre in North Otago, is highly concerned about the impact of unregulated visitors on penguin breeding and survival. Signs and viewing hides are erected to benefit visitors and protect wildlife, but visitors often ignore signs. Visitors block penguin access between nests and the sea at Katiki Point and arrive after dark, climbing gates and fences.
Based on a laser-operated counter, Penguin Rescue estimated 40,000 to 50,000 visitors to Katiki in the five month breeding season in 2014/2015. Penguins are wary of returning to their nest if they feel threatened. It seems that people are given priority over penguins in places with unregulated access.
Box-ticking tourists like free attractions
Penguin Rescue also report that many visitors come to see penguins at Katiki Point because it’s free and they can do it quickly. This box-ticking attitude is further demonstrated by people getting very close to penguins to take selfies for sharing on Instagram. These tourists have no regard for penguin welfare, or for the dedicated work of conservationists helping this endangered species survive, as well as providing a haven for other seabird species.
Penguin Rescue has documented the impact of human disturbance on the breeding success at Katiki Point where visitor access is high and unregulated. In the 2014/2015 breeding season, the number of fledged chicks at Katiki was half the number at a nearby colony without public access, and fledged chick weights were lower, affecting chick survival chances and future breeding.
Visitors can have a significant negative impact on yellow-eyed penguin survival if they are not mindful of the penguin’s needs. By learning more about wildlife beforehand, we enrich our own experience and help to protect animals for future people to enjoy.
© Tracy Brighten. Full article published at Nature in Mind.
Yellow-eyed penguin feeding chick by David Brighten
The Hoiho New Zealand’s Yellow-Eyed Penguin. Adele Vernon. Hodder & Stoughton. New Zealand. 1991.
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