Erect-crested Penguin(Eudyptes sclateri)
The Erect-crested penguin is a medium to large bird. Female penguins are usually smaller than males. The birds have long, slender bill, colored with brown-orange. The head, upper throat and cheeks of adult erected-crest penguins are dark black. The under parts of the bird are white in color. The upper parts, the body and tail of the penguin are colored with blue-black. They have a wide, yellow colored band, starting near the face over each eye, and composing an erect crest.
The plumage on the flippers is white ventrally with a black colored spot at the tip, and blue-black dorsally, fringed with white. Compared to adult penguins, juveniles are colored a bit different, and the crest on their head is shorter than that of adults. The upper parts of the chicks are grey-brown, and the under parts are white.
Habitat
During the winter, Erect-crested penguins live in sub-Antarctic waters, coming ashore only by the beginning of the breeding season. They usually breed on offshore islands in the south coast of New Zealand, including Antipodes, Bounty, Auckland and Campbell Islands. The nesting areas of these penguins are typically beaches as well as coastal cliffs and rocks. They prefer to nest on bare sites or these with scarce vegetation.
Diet
Erect-crested penguins are carnivores (piscivores). The diet of these birds primarily consists of fish, krill, crustaceans and cephalopods.
Breeding
Erect-crested penguins have monogamous mating system. The birds gather into large breeding colonies. In September, the penguins arrive at their breeding colonies. Usually, males arrive before females, finding the nesting site, which the pair used during the previous breeding season. Then, after 2 weeks, the females arrive. The pre-egg period is characterized by increased activity and even occasional fighting. The female typically lays 2 eggs in October. Egg laying takes about 3-5 days, during which the female does not eat. Both the male and the female incubate the eggs. As a general rule, the first laid egg usually doesn't hatch, so, after 35 days of incubation, a single chick hatches out. After 3 days, the female leaves, while the male stays with the hatchling, guarding the nest for the next 3-4 weeks. However, the mother returns every day to feed the young. At the age of 3 weeks, the hatchling joins a crèche of other chicks, but the parents continue to feed the juvenile. After fledging in January-February, the young penguin leaves, going out to sea.
Population
According to the IUCN Red List, they are classed as Endangered(EN). The most recent population survey conducted in 2011 found 34,226 nests on the Antipodes; on the Bounty Islands there were an estimated 26,000 nests in the same year, leading to an estimated 60,226 nests in total. This would equate to 120,452 nesting individuals, but it is assumed that only around 80% of mature individuals engage in breeding each year, so the number of mature individuals is estimated to number 150,000. Population trends indicate a severe decline between the mid-1970s and mid-1990s. On the Bounty Islands, estimated numbers were 115,000 pairs in 1978, apparently declining to 28,000 pairs by 1997, representing a 75% decline. However, the 1978 numbers have recently been called into question. Population surveys conducted in 1997, 2004, 2014, and 2019 indicate that parts of the Bounty Island population might actually have been relatively stable for the last two decades. However, as surveys covered only small portions of the Bounty Island archipelago, an ongoing population decline cannot be ruled out definitively. On the Antipodes Islands an estimated 115,000 breeding pairs were recorded in 1978, which declined extremely rapidly to 52,000 pairs by 1995. The rate of decline appears to have subsequently slowed somewhat; between 1995 and 2011 the number of penguin nests declined by 23%, although this is still equivalent to a 61% decline over three generations in this population.
Overall it appears that the population decline apparent until the 1990s has since slowed somewhat, which corresponds to the trend observed in the sympatrically breeding Southern Rockhopper Penguins. However, even if populations on Bounty Island had only declined from 28,000 pairs in 1978 to 26,000 pairs in 2011, the very rapid decline in the Antipodes still results in a decline of 52% over the past three generations (36 years). More reliable survey data is required to confirm the reduction in the rate of decline.
Threats
Although the reasons for reduction of their population are presently unknown, it is considered that the birds are affected by changes in oceanographic productivity throughout their range. These changes decrease breeding success of the birds, making adult penguins swim further in order to get food for their offspring.
Conservation
Conservation Actions Underway
Both islands are Nature Reserves and part of a World Heritage Site designated in 1998. Opportunistic monitoring of population size takes place.
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Conservation Actions Proposed
Survey a sample of Antipodes Island colonies every five years, and re-photograph photo-points from the 1978 and 1995 expeditions. Survey Proclamation Island (Bounty Islands) every five years. Compare aerial and ground surveys of the Bounty Islands to ascertain the viability of using the former method for monitoring colonies. Conduct detailed studies to determine foraging ranges, commercial fisheries interactions, and oceanographic or climatic changes. Bring in international agreements for the creation of further Marine Protected Areas and agreements on the regulation of fisheries, oil and other marine activities.