Spheniscus mendiculus
Galapagos penguin

Spheniscus mendiculus is found on the Galapagos Islands, off the western coast of Ecuador. Spheniscus mendiculus is a year-round resident of the majority of the 19 islands in the Galapagos chain. Most individuals are found on the two larger islands of Fernandina and Isabela. (Encyclopaedia Britannica and Inc., 2005; Harris, 1974; Sibley and Monroe Jr, 1990)

Galapagos penguins occupy coastal areas and offshore waters where the cold Cromwell Current brings food and other population-sustaining necessities into the vicinity. These birds rest on sandy shores and rocky beaches and nest on areas of sheltered coast. Galapagos penguins primarily breed on the larger islands of Fernandina and Isabela where they lay eggs in caves or holes found in the volcanic rock of the islands. When feeding, they will hunt for small fish and crustaceans in the coastal waters, diving to a depth of approximately 30 m. (Davis and Darby, 1990; Gorman, 1990; Lynch, 1997; Marshall Editions Developments Limited, 1990)

Galapagos penguins are fairly small penguins, averaging only 53 cm in height and ranging in weight from 1.7 to 2.6 kg. Sexual dimorphism exists, in that males are slightly larger than females. Galapagos penguins are the smallest members of the Spheniscus or "banded" penguins. Members of this species are mainly black in color with white accenting colors on various locations of the body and a large white frontal area. As in all banded penguins, the head is black with a white mark that begins above both eyes and circles back, down, and forward to the neck. They have the narrowest head-stripe of the banded penguins, a factor that distinguishes them from the similar Spheniscus magellanicus. Below the head stripe, S. mendiculus has a small black collar that merges into the back. Below the black collar there is another white stripe that runs the length of both sides of the body, followed by a black stripe that also runs the length of the body. (Lynch, 1997; Simpson, 1976)

Galapagos penguins can live for 15 to 20 years. Because of high mortality rates due to predation, starvation, climatic events, and human disturbance, most Galapagos penguins do not live to such ages.

Galapagos penguins are social animals that live in large colonies. By living in large colonies, these penguins can take advantage of group hunting and deterring predators. These penguins are awkward on land as a result of their short legs and small wings that provide little balance. When walking, Galapagos penguins waddle with outstretched wings. They are agile swimmers. (Gorman, 1990; Lynch, 1997; Simpson, 1976)

Home Range

Spheniscus mendiculus is endemic to the Galapagos archipelago. Galapagos penguins roam for food within the coastal waters of these islands, but specific home ranges are not reported. Galapagos penguins live in colonies and are territorial, protecting their nesting area from neighbors. Territory size depends on population density. (Lynch, 1997; Stonehouse, 1975)

Galapagos penguins rely on a series of vocal calls and sounds as well as a complex array of body movements for varying communication purposes. Vocalizations are crucial in helping to identify mates and chicks. These calls, along with body movements such as wing-flapping, help to deter egg-snatching predators. In courtship rituals, S. mendiculus relies heavily on displays and postures that advertise sexual status (paired or not paired), help to attract a mate, and reinforce the bond between the pair. Spheniscus mendiculus also uses vocalizations and body movements for general communication, such as greetings and displays of emotion. (Lynch, 1997; Sparks and Soper, 1987; Stonehouse, 1975)

Galapagos penguins are carnivorous and eat all types of small fish (no longer than 15 mm in length) and other small marine invertebrates. Prey species include anchovies (Engraulidae), sardines and pilchards (Cleupidae), and mullets (Mulgilidae). Galapagos penguins use their short wings to swim through the water and their small, stout beaks to capture small fish and other small marine organisms. Galapagos penguins usually hunt in groups and capture small prey by seizing them from below. The position of their eyes in relation to the beak means that they see prey best from a position below the prey. (Davis and Darby, 1990; Lynch, 1997; Muller-Schwarze, 1984)

Galapagos penguins lay their eggs in caves or holes in the volcanic rock, reducing predation on their eggs. They also vocalize, attack, and use body movements (wing-flapping, vocal calls, etc.) to frighten away predators. This is most effective when a group of penguins confronts a predator. Predators on young penguins include rats, crabs, and snakes. As adults, Galapagos penguins are preyed on by hawks and owls, as well as feral cats and dogs. When foraging for food in the water, Galapagos penguins are preyed on by sharks and other large, marine animals. The pattern of black and white countershading on their body makes them difficult to see underwater. A predator looking from above will see a black-colored backside of the penguin that blends in with the darker, deeper water. A predator seeing the penguin from below will see a white underside that blends with the lighter-colored, shallow water. (Davis and Darby, 1990; Muller-Schwarze, 1984; Simpson, 1976; Sparks and Soper, 1987)

Galapagos penguins are major predators of small fish and other marine invertebrates in the coastal waters of the Galapagos. They also act as prey for marine and avian predators in the Galapagos. (Davis and Darby, 1990; Simpson, 1976)

Galapagos penguins may cause minor economic harm to the seafood industry for humans. As S. mendiculus relies heavily on a diet of small fish, such as anchovies and sardines, collectively the species can have an effect on the number of small fish available to catch for human consumption in their range. It has been shown that a penguin population can eat upwards of 6,000 to 7,000 tons of food locally, approximately 3,000 tons of that total has some economic value to humans. (Simpson, 1976)

Galapagos penguins provide economic value to humans who use this species and its coastal habitat to promote ecotourism. Many tourists and avid birdwatchers will pay to travel and visit the habitats of the Galapagos penguins. (Harris, 1974)

According to the IUCN Red List and the United States Endangered Species Act, Galapagos penguins are currently listed as endangered. Due to climatic changes brought about by El Niño and La Niña cycles, the food supply available to the Galapagos penguins varies greatly. These unpredictable shifts in food supply often lead to starvation and deaths and a substantial decline in the already dwindling penguin population. Furthermore, human disturbances and predation are major factors contributing to the decline of S. mendiculus. Human disturbance is the main cause for ecosystem harm that affects the nesting grounds of Galapagos penguins. Few efforts are underway to protect S. mendiculus. However, recently the Galapagos Conservation Trust launched the Sylvia Harcourt-Carrasco Bird Life Fund for Galapagos that will aim much of its efforts at conserving the population of Galapagos penguins. This fund provides a push for the conservation of S. mendiculus that may lead to other conservation actions, and eventually to a restored, healthy population. (Benthall, 2006; Bingham, 2006)