Animal Spotlight: Galapagos Penguin

Taxonomy:galapagos_penguin_spheniscus_mendiculus_-isabela2-702x1024

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Aves
  • Order: Sphenisciformes
  • Family: Spheniscus
  • Genus: mendiculus
  • Average Weight: 5.5 lbs (2.5 kg)
  • Average Height: 20 in (51 cm)
  • Average Lifespan: 15 – 20 years

Endemic to the Galapagos Islands, Ecuador and named after where it lives, the Galapagos penguin is the smallest of the South American penguin species. It is also the smallest population of a penguin species. It is estimated that there are fewer than 2,000 individuals with less than half of the estimate able to breed.

Approximately 95% of the population occurs on the western islands of Fernandina and Isabela Islands. There are smaller colonies are also found on other nearby islands and in the general vicinity.

They are the only known species of penguin that is able to successfully live so close to the equator. The intense rays of sunshine are a known problem for the Galapagos penguins but the nights and waters, due to the currents that come into the area, are cool and provide shade. It nests in cracks, caves and depressions in the island’s lava flows.

Physical Appearance

The Galapagos penguin has a black head and back, with a narrow white line extending from the throat around the head to the corner of the eye. Its underparts are white, with two black bands extending across the breast, extending to its mottled black feet. Individual-specific spots on chest and abdomen stay throughout their lifetime. Unlike other penguins in its family, they lack the white tail spot. Its upper bill and tip of the lower bill are also black, with the remainder of the lower bill and surrounding skin around to the eye being pinkish yellow. Compared to other penguin species, the Galapagos penguin has a longer and more slender bill.

gal10_3868
Via PhotoVolcanica

The only physical difference between the genders is the size. Females are generally smaller than males.

Juveniles have a completely dark head and lack the dark breast bands seen in adults. Fledgling plumage turns from a blue-gray to grayish and from grayish to brown before the first molt. Most fledglings have white cheeks that will eventually turn grayer. Their white feet will turn darker and become mottled as they mature.

Diet:

A Galapagos penguin’s diet comprises almost entirely of small schooling fish, particularly mullet and sardines. However, it will feed on other animals they find in the waters around them, including crustaceans, krill, squid, and larger fish species, if those primary sources of food aren’t readily available in enough supply to satisfy the population.

Foraging is restricted to daylight hours and the penguins will rarely leave more than a few kilometers from the breeding site, preferring to stay close to the shoreline. The majority of the food they want is brought in by the current.

Behavior:

Male and female penguins form pair bonds for life, enabling them to begin breeding quickly during times of high food abundance. This bond is reinforced by mutual preening and bill tapping. Mutual preening, also known as allopreening, is generally only observed around breeding season. Standing near to each other, socializing individuals or established pairs initially preen themselves. After a brief pause, one of the birds starts to preen the other on the head or neck. The other bird may continue to preen itself or may reciprocate this behavior.

humbzoo2011b_0019s
A bonded pair preening each other. Via PhotoVolcanica

Bill dueling is often observed when one bird closely approaches another, sometimes after landing at the beach. The birds face each other and vigorously shake their heads from side to side, resulting in repeated clattering of the tips of the bills. Paired or unpaired penguins may perform this behavior. In the former case the penguins remain close after performing this ritual and may either simply relax or alternatively flipper-patting, which is performed by the male who rapidly pats his partner as he edges round to the back of her, and often copulation may follow.

And unlike most other penguins, Galapagos penguins have no particular breeding season and can produce as many as three clutches in a single year. The flexibility of breeding allows for the penguins to delay breeding completely until food resources improve.

Galapagos penguins undergo their molt prior to breeding, and may molt twice in a single year. Molting birds generally avoid the water, but because the equatorial waters are warm, birds that become underweight are able to go to sea to feed, rather than face starvation.

By moulting prior to breeding, Galapagos penguins are able to ensure that early failure of their food resources will not result in starvation during the moult. If food supplies disappear prior to the completion of breeding, than breeding success will suffer, but the adults will have the highest chance of surviving the shortage. It is the survival of the adult population that ultimately ensures the survival of the species.

Breeding is stimulated amongst Galapagos Penguins by a drop in sea surface temperatures to below about 24 degrees Celsius, which corresponds to the presence of nutrient rich currents, and in turn an abundance of prey. Nests are made along turbulent rocky shores within about 50m of the water, mostly on the islands of Fernandina and Isabela. Burrows are sometimes dug in suitable volcanic deposits, but often nests are in caves or crevices in old fissured larva. Adults remain around the breeding sites throughout the year and will spend an increasing amount of time on land during the period before egg-laying. Males will tend to occupy the nests as egg-laying approaches and have been observed braying at dawn and dusk until the female lays her eggs.

galapagos-penguin

Two eggs are laid four days apart. Usually the second egg is slightly less likely to hatch, possibly due to lack of fertilization or poorer egg composition. Incubation can take up to 40 days and the duty is shared equally by the male and female. Chicks are then brooded for the first 30 days until they develop a mesophile plumage that is brown above and white below to protect them from the sun.

After 65 days, fledging will occur. Fledglings have greyish black upper parts and white underparts, but lack the white lines of the adults. Instead, they have paler cheeks which indicate where the thin white head line will later develop.

Conservation and Threats:

These penguins are threatened by pollution, bycatch, and climate. Introduced species, such as dogs, carry diseases that can spread to the penguins as well, and cats pose as a predatory threat. However, the main threat facing this unique penguin is the increasing frequency of El Niño Southern Oscillations (ENSO). These ENSO events reduce the strength of the cool currents that this species relies on to survive and causes fluctuations in its supply of prey. During these periods of food shortages, the Galapagos penguin will forage individually and will also make no attempt to breed until sea temperatures decrease once again.

The 1982-1983 ENSO resulted in a catastrophic loss of 77% of the Galapagos penguin population due to starvation. A slow period of recovery followed, but the 1997-1998 ENSO resulted in another precipitous population crash of 66%. Such events may have a disproportionate effect on females, which can skew the sex ratio and make recovery even slower.

galapagosAll populations of the Galapagos penguin occur within the Galapagos National Park and Marine Reserve. At present, all populations are closely monitored and feral animals are controlled. nets in foraging areas, preventing coastal developments in breeding areas, and providing nest-boxes in predator free areas to allow research into the reproductive success of this species

As the population of the diminutive and uniquely adapted Galapagos penguin is so small and precarious, and restricted to just one breeding location, unfortunately this species is extremely vulnerable to extinction.

It is listed as endangered on the IUCN Red List.

Interesting Facts

  • The Galapagos penguin is thought to be most closely to the African penguin and the Humboldt penguin found along the coast of Peru and Chile.
  • Unlike many other penguin species, including all surface-nesting species, Galapagos Penguin chicks do not form creches, also known as nurseries. They generally stay in or close to their own nests until shortly before fledging.
  • Researchers have recorded the penguins sleeping with their flippers outward. It is believed to prevent the heat from escaping their bodies.
  • They have also been seen placing their flippers over their feet as they walked on land, believed to be an effort to prevent the sunlight from burning their sensitive feet, as well as panting.
  • The Galapagos penguin is the only penguin found on the Northern Hemisphere

References + For More Reading

WWF: Galapagos Penguin

Galapagos penguin (Spheniscus mendiculus)

Galapagos Penguin

Penguin World: Galapagos Penguin

IUCN: Spheniscus mendiculus

A-Z Animals: Galapagos Penguin

MarineBio: Spheniscus mendiculus

Penguin Studies

ADW: Spheniscus mendiculus Galapagos penguin

Photo Volcanica: Galapagos Penguin

Galapagos Penguin (Spheniscus mendiculus)

 

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