Snares Penguin
Encyclopedia
The Snares Penguin also known as the Snares Crested Penguin and the Snares Islands Penguin, is a penguin
from New Zealand
. The species breeds on The Snares
, a group of islands off the southern coast of the South Island
.
This is a medium-small, yellow-crested penguin, at a size of 50-70 cm (20-28 in) and a weight of 2.5–4 kg (5.5-8.8 lbs). It has dark blue-black upperparts and white underparts. It has a bright yellow eyebrow-stripe which extends over the eye to form a drooping, bushy crest. It has bare pink skin at the base of its large red-brown bill.
This penguin nests in small (10 nests) to large (1200 nests) colonies under forest cover or the open. Main colonies are located on North East Island, other colonies are established on Broughton Island
as well as the rocky Western Chain. The Snares penguins' main prey is krill
(~60% of diet), supplemented by squid
(~20%) and small fish
(~20%).
The species is currently rated as 'vulnerable' by the IUCN as its breeding range is restricted to one small island group. The current population is estimated at around 25,000 breeding pairs.
in Buller’s
“A History of the Birds of New Zealand” are evidence that this is the same penguin previously identified by Hutton. However, there is some debate over the classification of this penguin, and Oliver was able to successfully propose that a few slight anatomical differences did exist between the snares penguins and the early description and illustration, leading the snares penguin to be called robustus instead of atratus. [12]
(Eudyptes Pachyrhynchus), which is related by the genus of crested penguins (Eudyptes). Snares penguins can be distinguished from fjordland penguins by a patch of skin at the base of their beaks. [2] Snares penguins are similarly colored to other species of penguins, having a black head, back and flippers with a white belly. A bright-yellow crest, beginning at the base of the bill, runs along the upper part of the head on both sides and ends at the back of the head. They have thick reddish-brown beaks, traced with light pink skin at the base. [10] Their eyes are generally described as a bright red-brown color, but this coloration can vary somewhat between individuals and in different lighting. [12] The color patterns under the wings differ from individual to individual, so it is not a good characteristic for species identification. [11]
Snares penguins can make a large variety of vocal noises. It is difficult to verbally describe these noises but they can range from hisses and explosive cries when threatened to rhythmical braying a trumpeting sounds that can be heard from long distances at sea. [12]
outside of the breeding season, it is not thought that they migrate far in the winters. Occasional sitings have occurred on the coasts of Tasmania
, southern Australia
, the Chatham Islands
, Stewart Island, and the southern New Zealand mainland. [1, 9] There are approximately 25,000 living pairs of snares penguins. [10]
australis, small fish, and cephalopods
. One study found that about 60 percent of the mass of stomach contents from snares penguins consisted of krill, 30 percent was fish, and about 10 percent was cephalopods. The researchers concluded that the number of fish otoliths
and cephalopod beaks indicated the importance of these types of prey to adult penguins while at sea. [5] Another study reports the diet consisting of about 55 percent krill, 24 percent fish, and 21 percent cephalopods, also suggesting that fish and cephalopods are more important prey types than the percentages of stomach composition indicate. [6] Yearly, two week long foraging trips by males has been found to be synchronized with spring plankton
blooms, as they are reliable predictors of food sources. Upon the return of the males, the females go on somewhat long foraging trips (less than a week), returning in time for her chicks to hatch. Then, the female is the lone provider of food, and she embarks on short voyaging trips (about 1 to three days). [6] Snares penguins use shallow pursuit diving to catch prey, a strategy used by other penguin species as well. This hunting strategy consists of propelling themselves through the water using their webbed feet and flippers, reaching speeds of up to 15 miles per hour. [10]
Predators of adult snares penguins are sea lions and leopard seals. Their eggs and chicks are hunted by skuas and petrels. [2]
”. Egg-size dimorphism is particularly large in snares penguins, and the larger egg hatching first only accentuates the sibling size difference. [3] Hatching pattern and size-dimorphic eggs are two of the mechanisms by which birds can change their breeding pattern in response to environmental and breeding conditions. In altricial
birds, such as snares penguins, egg-size variation and asynchronous hatching are adaptive mechanisms that may lead to brood reduction. However, snares penguins and other members of their genus, Eudyptes, differ from most other birds in that their last laid egg is larger and hatches first rather than being the smallest and last to hatch. [8]
at approximately 11 weeks. [2]
around the islands that would deplete the penguins’ food source, increasing water temperatures from global warming
driving prey away, and pollution
. [1, 9] The New Zealand government has taken action to protect the Snares Islands habitats and marine feeding grounds. [10]
Penguin
Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...
from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. The species breeds on The Snares
The Snares
Snares Islands/Tini Heke is a small island group situated approximately 200 kilometres south of New Zealand's South Island and to the south-south-west of Stewart Island/Rakiura. The Snares consist of the main island North East Island and the smaller Broughton Island as well as the somewhat...
, a group of islands off the southern coast of the South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
.
This is a medium-small, yellow-crested penguin, at a size of 50-70 cm (20-28 in) and a weight of 2.5–4 kg (5.5-8.8 lbs). It has dark blue-black upperparts and white underparts. It has a bright yellow eyebrow-stripe which extends over the eye to form a drooping, bushy crest. It has bare pink skin at the base of its large red-brown bill.
Broughton Island, New Zealand
Broughton Island is the second largest island of The Snares, at just off the South Promontory of the main island North East Island, which lies approximately south of New Zealand's South Island. The island is some long in SW direction, and the highest elevation is...
as well as the rocky Western Chain. The Snares penguins' main prey is krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...
(~60% of diet), supplemented by squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
(~20%) and small fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
(~20%).
The species is currently rated as 'vulnerable' by the IUCN as its breeding range is restricted to one small island group. The current population is estimated at around 25,000 breeding pairs.
Nomenclature
The snares penguin was originally collected in 1874 and named atrata by Hutton. However, he lost his sample at sea before a full speciation could be identified. A description written by Hutton and an illustration done by KeulemansJohn Gerrard Keulemans
Johannes Gerardus Keulemans was a Dutch bird illustrator.-Biography and Work:...
in Buller’s
Walter Buller
Walter Lawry Buller KCMG was a New Zealand lawyer, naturalist and ornithologist.Buller was the author of A History of the Birds of New Zealand , with illustrations by John Gerrard Keulemans. In 1882 he produced the Manual of the Birds of New Zealand as a cheaper, popular alternative...
“A History of the Birds of New Zealand” are evidence that this is the same penguin previously identified by Hutton. However, there is some debate over the classification of this penguin, and Oliver was able to successfully propose that a few slight anatomical differences did exist between the snares penguins and the early description and illustration, leading the snares penguin to be called robustus instead of atratus. [12]
Description
The snares penguin is often compared to the fjordland penguinFiordland Penguin
The Fiordland Crested Penguin , also known as Tawaki , is a species of crested penguin from New Zealand...
(Eudyptes Pachyrhynchus), which is related by the genus of crested penguins (Eudyptes). Snares penguins can be distinguished from fjordland penguins by a patch of skin at the base of their beaks. [2] Snares penguins are similarly colored to other species of penguins, having a black head, back and flippers with a white belly. A bright-yellow crest, beginning at the base of the bill, runs along the upper part of the head on both sides and ends at the back of the head. They have thick reddish-brown beaks, traced with light pink skin at the base. [10] Their eyes are generally described as a bright red-brown color, but this coloration can vary somewhat between individuals and in different lighting. [12] The color patterns under the wings differ from individual to individual, so it is not a good characteristic for species identification. [11]
Snares penguins can make a large variety of vocal noises. It is difficult to verbally describe these noises but they can range from hisses and explosive cries when threatened to rhythmical braying a trumpeting sounds that can be heard from long distances at sea. [12]
Range and Abundance
Snares penguins are named after the place in which they breed: the Snares Islands. The Snares Islands are a small group of islands off the coast of southern New Zealand. Although little is known of their range and migrationAnimal migration
Animal migration is the relatively long-distance movement of individuals, usually on a seasonal basis. It is a ubiquitous phenomenon, found in all major animal groups, including birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. The trigger for the migration may be local...
outside of the breeding season, it is not thought that they migrate far in the winters. Occasional sitings have occurred on the coasts of Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, southern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, the Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...
, Stewart Island, and the southern New Zealand mainland. [1, 9] There are approximately 25,000 living pairs of snares penguins. [10]
Habitat
Snares penguins nest in dense colonies under the tree cover of the Olearia forests or on coastal rocks. [11] To build a nest, the penguins dig up shallow holes in the ground and layer the bottom with grass, leaves, twigs, peat, or pebbles. [10] A small rim of mud is added to the rim of the nest to raise it above ground level. [12] Vegetation at nesting sites dies dues to the dense nesting activities, and the colony moves to a new nesting site. [1] Colonies nesting near streams may have some advantage, as the stream provides water for drinking and bathing. However, it is not essential that nesting colonies are located near a stream since many are far from any streams. [12]Feeding Habits
The diets of snares penguins usually consist of krill of the species NyctiphanesNyctiphanes
Nyctiphanes is a genus of krill, containing the following species:*Nyctiphanes australis G. O. Sars, 1883*Nyctiphanes capensis Hansen, 1911*Nyctiphanes couchii *Nyctiphanes simplex Hansen, 1911...
australis, small fish, and cephalopods
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
. One study found that about 60 percent of the mass of stomach contents from snares penguins consisted of krill, 30 percent was fish, and about 10 percent was cephalopods. The researchers concluded that the number of fish otoliths
Otolith
An otolith, , also called statoconium or otoconium is a structure in the saccule or utricle of the inner ear, specifically in the vestibular labyrinth of vertebrates. The saccule and utricle, in turn, together make the otolith organs. They are sensitive to gravity and linear acceleration...
and cephalopod beaks indicated the importance of these types of prey to adult penguins while at sea. [5] Another study reports the diet consisting of about 55 percent krill, 24 percent fish, and 21 percent cephalopods, also suggesting that fish and cephalopods are more important prey types than the percentages of stomach composition indicate. [6] Yearly, two week long foraging trips by males has been found to be synchronized with spring plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
blooms, as they are reliable predictors of food sources. Upon the return of the males, the females go on somewhat long foraging trips (less than a week), returning in time for her chicks to hatch. Then, the female is the lone provider of food, and she embarks on short voyaging trips (about 1 to three days). [6] Snares penguins use shallow pursuit diving to catch prey, a strategy used by other penguin species as well. This hunting strategy consists of propelling themselves through the water using their webbed feet and flippers, reaching speeds of up to 15 miles per hour. [10]
Predators of adult snares penguins are sea lions and leopard seals. Their eggs and chicks are hunted by skuas and petrels. [2]
Reproductive Behavior
The breeding season of snares penguins occurs in the summer of New Zealand, beginning in early September and ending in late January. [3] Snares penguins begin reproducing in the age range of five to nine years old. [12] To court the females, single males stand erect with their wings spread out and pumping their chest. [1] It is likely that the pairs remain faithful to each other for more than one season. The pairs then build a nest, most of the work being done by the male. [12] The female lays two eggs, typically about three to five days apart, which hatch 31-37 days later. The second laid egg is up to 85 percent larger than the first and also hatches first. The smaller, last-hatched chick usually doesn’t survive due to being outcompeted by its sibling or “siblicideSiblicide
Siblicide is the killing of an infant individual by its close relatives . It may occur directly between siblings or be mediated by the parents. The evolutionary drivers may be either indirect benefits for the genetic viability of a population or direct benefits for the perpetrators...
”. Egg-size dimorphism is particularly large in snares penguins, and the larger egg hatching first only accentuates the sibling size difference. [3] Hatching pattern and size-dimorphic eggs are two of the mechanisms by which birds can change their breeding pattern in response to environmental and breeding conditions. In altricial
Altricial
Altricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
birds, such as snares penguins, egg-size variation and asynchronous hatching are adaptive mechanisms that may lead to brood reduction. However, snares penguins and other members of their genus, Eudyptes, differ from most other birds in that their last laid egg is larger and hatches first rather than being the smallest and last to hatch. [8]
Care of Offspring
Egg incubation does not occur until both eggs have been laid, and they are usually incubated one in front of the other. The smaller, first-laid egg is often placed in the anterior position for incubation, which is thought to be the less favorable location since they have lower and more variable temperatures during incubation. Although the smaller, first egg receives less favorable incubation, it was found that egg-size dimorphism affects the hatching pattern in snares penguins instead of egg incubation position. [4] Both parents partake in incubating the eggs. For the first ten days, they alternate. Then the male leaves for an extended period (about 12 days) to forage for food, while the mother stays with the eggs. When he returns, the roles are reversed. Also, upon his return, the pair engages in a display of bowing and trumpeting, which further strengthens their bond. For the first three weeks after hatching, the male guards the chicks from predators while the female searches for food, returning each day to feed her offspring. [1] It was observed that parents can recognize their chicks and chicks can recognize their parents. The study found that calls between chick and parent were more important for recognition than visual cues. [7] The parents provide food for their young each day until it has molted and can forage for its own food. [10] The chicks fledgeFledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
at approximately 11 weeks. [2]
Conservation
Although snares penguins are not currently threatened, they are considered a vulnerable species. If a threat arose, it could quickly wipe out their population because their breeding grounds are confined to a small island group. Possible threats include the introduction of a new predator, overfishingOverfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
around the islands that would deplete the penguins’ food source, increasing water temperatures from global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
driving prey away, and pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
. [1, 9] The New Zealand government has taken action to protect the Snares Islands habitats and marine feeding grounds. [10]
External links
- In-depth information on Snares penguins and their biology
- Snares penguins from "International Penguin Conservation" Web Site
- Penguin World: Snares penguin
- ARKive - images and movies of the snares crested penguin (Eudyptes robustus)
- www.pinguins.info : information about all species of penguins
- TerraNature - Snares crested penguin, images and information on six New Zealand penguins