Ornithology

Big-crested penguin

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Big-crested and Rockhopper penguins. Antique print by Henrik Gronvold

Also called Erect-crested penguin. The Big-crested penguin (scientific name: Eudyptes sclateri) is one of seventeen species of flightless birds in the family of penguins. It is one of six "Crested penguins" in the genus Eudyptes which also includes the Rockhopper, Macaroni, Fiordland crested, Royal and Snares crested penguins.

 

 

Conservation Status

 

Scientific Classification

Kingdom: Animalia
Phylum:--- Chordata
Class:------ Aves (Birds)
Order:-------- Sphenisciformes
Family:-------- Spheniscidae (Penguins)
Genus:--------- Eudyptes (Crested Penguins)
Species:-------- Eudyptes sclateri Buller 1888

Like all penguins, the Big-crested penguin is characterized by its erect posture, stiff wings (flippers), excellent swimming ability, awkward movement out of water and distinctive coloring. The black back and white front, make penguins difficult to sight when they are swimming, blending against the sea from above and the sky from below. 

Physical Description

Big-crested penguins are perhaps some of the most mysterious of all penguin species. This bird is one of the largest of the crested penguins and shares with the Fiordland and Snares crested penguins the distinctive feature of an upward-sweeping crest of long, yellow brush-like feathers above each eye, extending from the base of the bill to the top of the head. Unlike other crested penguins, however, the big-crested penguin is able to raise and lower these stiff crest feathers. With its black back and white belly, this species sports the classic penguin tuxedo-attired look. The upper sides of the wings are black with a white edge and the lower sides are white with a black patch at the tip. Males are generally larger than females, and both sexes have long, slender beaks that are dark brown-orange in color.

Diagnostic Description: Eudyptes sclateri are approximately 65 cm tall and at the maximum body mass, which occurs before molting, of about 6.5 kilograms. The males are generally larger. In the adult, the coloration of the head, upper throat, and cheeks are a very dark black. There is a broad yellow stripe that starts near the face, which rises over the eye to form the erect crest. The body and upper parts, along with the tail, are blue-black while the under parts are white. The dorsal side of the flipper is blue-black with a white edge, while the ventral side is white with a black patch at the tip of the flipper. The beak is long and slim with brown-orange coloring. The chicks have gray-brown upper parts and white under parts. Juveniles have a slight coloration difference from the adults but the main defining feature is the shorter crest.

Reproduction

The Big-crested penguin is an extremely social bird that breeds in large, raucous colonies of several thousand pairs, usually alongside rockhopper penguins (Eudyptes chrysocome). Males usually return to the vicinity of the previous nesting site in September, and compete fiercely for prime nesting sites

This species uses a number of displays and vocalizations, utilized particularly in the courtship and breeding season and in aggressive territorial behavior during mate matching or when defending nesting sites. Courtship displays include an enthusiastic greeting with an open bill, vertical head swinging, trumpeting, quivering, bowing and preening. Aggressive displays include use of the crests, growling and barking, while direct fighting involves twisting of locked bills or biting of the enemy on the neck while beating them with the flipper.

The pre-egg stage is marked by considerable activity, notably fighting. The females and males work together to construct nests of mud, stones and grass.The nest site is characteristically on flat rocky ground no higher than  seventy meters above sea level. The female, who usually forms the nest cup, rotates on her breast, kicking and pushing dirt away from the cup with her feet. The male then usually rings the nest cup with rocks and mud and lines it with grass if available.

Egg laying occurs in early October and lasts three to five days, during which time, the female fasts. The clutch normally contains two eggs, the second being noticeably larger than the first (up to twice as large) and is the only the larger being steadfastly incubated. The eggs are normally a chalky pale blue or green and later become a light brown. After the second egg is laid, incubation begins and lasts for approximately thirty-five days. Usually, the smaller first egg is lost, (at least ninety-eight percent of the time) and the second, larger egg is the only one to hatch. The male and female take turns incubating the egg for about 35 days.

Two to three days after the eggs hatch, the female disappears to sea and leaves the male to guard the nest. The guard stage lasts three to four weeks, during which period the male fasts and the female returns daily to feed the chick regurgitated food. The fledgling period, when the chicks leave the island, normally begins in February, at which point the chick enters adulthood. Adults return to the sea for the (austral) winter after molting in March.

Behavior

Eudyptes sclateri are gregarious birds with many displays and vocalizations. The mating pairs usually recognize each other by sight and vocalizations. Calls are low-pitched phrases given at a steady rate. They are usually harsh and composed of pulsed phrases. Calling occurs only during the daytime. The chicks also cheep, and these calls are usually shorter and less complex than adults, as well as being higher pitched. Displays are very extensive including an ecstatic display with an open bill, which is normally used in courtship. Aggressive displays involve the use of the crest, while other displays include vertical head swinging, mutual displays and trumpeting, shoulders hunched posture, quivering, bowing, and mutual preening. These displays normally arise in sexual courtship behavior. Fighting displays and sounds include a lowered head with growling or barking, and direct fighting with twisting of locked bills or biting the enemy on the neck while beating with the flipper. The fighting displays are usually seen during mate matching or when defending nesting sites, which can be very competitive.

Distribution

The majority of the breeding population occurs on the Bounty and Antipodes Islands, with smaller numbers on the Aucklandand Campbell Islands, New Zealand. The non-breeding winter distribution is spent at sea in the sub-Antarctic oceans, although the exact location is unknown.

Habitat

Nests are constructed in large, dense colonies on rocky terrain, often without substantial soil or vegetation, up to 75 meters above sea level.

During the winter months at sea, Big-crested penguins remain in the cool marine waters of the sub-antarctic. Their exact marine positions has not been determined. They normally breed on the rocky Antipodes, Bounty, Campbell, and Auckland Islands in colonies that also include E. chrysocome. The islands exhibit rocky coastlines, with cliffs that provide for well-protected nests. The vegetation is sparse, normally consisting of short grasses and shrubs. These islands are located in the sub-antarctic waters south of New Zealand.

Feeding Habits

Little is known about the feeding habits of the erect-crested penguin, but the chief sources of food are thought to be krill, crustaceans and squid, occasionally supplemented by small fish.

Conservation Status

This species is classified as Endangered (EN) on the IUCN Red List 2006. All the islands on which the erect-crested penguin is found are nature reserves and, as of 1998, became part a World Heritage site. Cattle and sheep were eradicated from Campbell Island in 1984 and 1992 respectively, and introduced brown rats (Rattus norvegicus) have also been successfully removed from Campbell Island.

Scientists have observed a species population decline of at least fifty percent in the last forty-five years. This species has a restricted breeding range, which intrinsically leads to conservation threats. Additionally, the Big-crested penguin does not appear on the CITES list which indicates the penguin is not thought to be hunted or used in trading by humans.

Threats

Although still somewhat abundant, the Big-crested penguin is considered endangered because it is thought to have undergone significant declines of at least fifty percent over the last 45 years, a pattern that is only expected to continue. Furthermore, the species very small and restricted breeding range leaves it particularly vulnerable. The reasons for this decline are not fully understood, but are believed to be associated with marine factors, as predation on land during the breeding season is unlikely to be significant, since there are no mammalian predators on the Bounty or Antipodes Islands, except for mice on the main Antipodes Island.

Economic Importance for Humans

Big-crested penguins are of little economic importance to mankind. They are not caught for food or used in any other way by humans.

Further Reading 

Glossary

Citation

Saundry, P., & Life, E. (2011). Big-crested penguin. Retrieved from http://www.eoearth.org/view/article/51cbed127896bb431f68f815

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