Yellow-eyed penguin/hoiho nest numbers have hit rock bottom. Despite the efforts of local conservation groups working hard to keep chicks alive, less than 190 breeding pairs have been counted on the Otago coast this season. In 2012, there were an estimated 491 breeding pairs.
Egg hatching success had remained around 85% in North Otago and on the Otago Peninsula, with avian diphtheria infection rates being up to 100% at some breeding sites. Some chicks had perished on hot days as they were still under full protection of their parent's body.
"We've lost about 50 chicks, despite our more intensive efforts this season," Coastal Otago Biodiversity Ranger Mel Young said. Approximately 115 chicks at monitored sites from the Peninsula to Moeraki had survived.
Management attempting to address illness and dehydration, has included removing the oral diphtheria lesions, which can prevent feeding and breathing, as well as feeding chicks a smoothie of salmon and rehydration fluids every few days.
"There's no obvious pattern to the outbreak of infection, but most chicks that have been infected have also been underweight. We can't be sure if illness or starvation has driven the observed mortality, but the heat certainly has played a large part too." Ms. Young said. Temperatures in excess of 16°C caused discomfort to adult penguins.
Human disturbance at unregulated breeding areas is also of ongoing concern, as adult penguins returned ashore regularly to feed chicks.
"We recommend that people take a tour to see yellow-eyed penguins this summer. Tour operators are experienced in guiding visitors appropriately to minimise disturbance and ensure that birds are not disturbed when they come ashore to feed their chicks" said Sue Murray, General Manager, Yellow-eyed Penguin Trust.
Tour operators Penguin Place have been heavily involved in management of chick survival over the last few weeks, and have recorded only one chick death.
Over the last three seasons Penguin Place's rehabilitation facility has cared for over 400 yellow-eyed penguins that would have otherwise failed to survive in the wild. Funding for the rehabilitation centre came completely from Penguin Place's guided conservation tours, with their staff working closely with local vets and experts to increase survival of injured and underweight yellow-eyed penguins.
Rehabilitation Manager Julia Reid said "Our facility will usually become busy from mid-late January as underweight chicks begin to be brought in from monitored sites on the Otago Peninsula and the Catlins. We are preparing for this influx by stocking up on quality fish and medical supplies." Mrs. Reid said.
DOC and local conservation groups will now be focused on the most critical part of the season, when injured, underweight and moult-compromised penguins may need to be rehabilitated.
Patrolling of monitoring areas will continue throughout the season to ensure penguins are in good condition as they prepare their annual moult. Underweight or injured birds will be removed for veterinary treatment and rehabilitation.
A mass mortality event, assumed to be caused by an unidentified toxic agent, killed more than 70 adults and juveniles on Otago Peninsula in early 2013.
In December 2013, many chicks starved early in the season. Those that survived to fledge-age were emaciated and unlikely to survive at sea. Many adults and juveniles were in poor condition by early 2014 and unable to moult without intervention. The number of penguins needing rehabilitation increased to 329 across three Otago rehabilitation centres, straining resources and requiring tonnes of fish supplies.
More than 55 adult penguins were maimed in suspected barracouta attacks from January to April this year.
Avian diphtheria has also affected numbers as the disease has infected 90% of hoiho chicks on the Otago coast in alternate years. The disease causes ulceration of penguin chicks' mouths, making it difficult for them to eat and breathe, and can become fatal if left untreated. DOC and its partners have provided supportive therapies including treatment of avian diphtheria and supplementary feeding for infected chicks. This is the first season where avian diphtheria has presented non-bimodally, with high levels of infection usually observed in even-numbered years.
In addition, interference from humans and livestock at breeding areas, heat stress, predation by stoats and ferrets, and dog attacks have reduced the number of chicks surviving to fledge age in recent years. Human interference includes unregulated tourism.
Before the appearance of avian diphtheria, only 19% of hoiho chicks that fledged survived their juvenile year. In the last few years, only a small number of juvenile and 2-year old penguins have been seen.
The penguin communities will work closely together over the coming months to manage and mitigate detrimental events affecting hoiho survival throughout the breeding season. As well as DOC and the Yellow-eyed Penguin Trust, other parties involved are Penguin Rescue, Penguin Place, Southland Forest and Bird, Otago University, landowners, local Rūnanga and volunteers.
Penguin Place's rehab facility is fully funded by guided tours to see wild yellow-eyed penguins on the Otago Peninsula. Tourists and locals wishing learn more about yellow-eyed penguins and their situation on the mainland of New Zealand, which includes the opportunity to participate in their conservation project by planting a native tree, are encouraged to join one of Penguin Place's informative tours running from 10.15am daily.