Overview

Brief Summary

Biology

It is thought that the loss of flight in this species is the result of a long period of evolution on isolated, predator-free islands, as well as the fact that they forage in a very small area (7). Unlike penguins, which 'fly' through the water using their flipper-like wings, the flightless cormorant propels itself by kicking its strongly-built legs (7). The flightless cormorant feeds on octopuses, eels and bottom-dwelling fishes, which it hunts for by making pursuit-dives (3). All cormorants are aquatic predators, but their feathers are not waterproof. A behaviour characteristic of the family is to adopt a stance after emerging from the water in which the wings are held open in order to dry the feathers. Flightless cormorants retain this behaviour, and are commonly seen holding their small ragged wings at their sides (7). Nesting tends to take place during the coldest months (July-October), when marine food is at its most abundant and the risk of heat stress to the chicks is decreased (2). At this time, breeding colonies consisting of around 12 pairs form (3). The courtship behaviour of this species begins in the sea; the male and female swim around each other with their necks bent into a snake-like position. They then move onto land. The bulky seaweed nest, located just above the high-tide mark, is augmented with 'gifts' including pieces of flotsam such as rope and bottle caps, which are presented to the female by the male (3) (7). Two to three whitish eggs are laid; they are incubated by both parents (3) (7). After the chicks hatch, the parents share the duties of brooding and feeding (7). If food is plentiful, the female may leave the male to continue to care for the chick as it approaches independence; she will then produce a second brood with another male (7). This high breeding potential allows the population to quickly recover from declines in numbers (7).
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Description

The flightless cormorant, also known as the Galapagos cormorant, is a large, blackish coloured bird. The tiny, scruffy-looking wings indicate the flightless habit of the species (2). This species is the only flightless cormorant and the heaviest member of the family (4). Like other flightless birds, the sternum (breastbone) has lost the pronounced keel, which in most birds is the site of attachment for the well-developed flight muscles (3). In fact, this species is so different to other cormorants, that some experts place it in a separate genus (Compsohalieus) (5). The upperparts of the flightless cormorant are blackish and the underparts are brown. The long beak is hooked at the tip and the eye is turquoise (2). Like all members of the cormorant family, all four toes are joined by webbed skin (6). Males and females are similar in appearance, although males tend to be much larger (2). Juveniles are generally similar to adults but differ in that they are glossy black in colour with a dark eye. Adults produce low growling vocalisations (2).
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Distribution

Range Description

Phalacrocorax harrisi is endemic to Fernandina and Isabela in the Galpagos Islands, Ecuador. It is found around most of the coast of Fernandina (mainly on the east), but only on the north and west coasts of Isabela (Valle and Coulter 1987, H. Vargas and F. Cruz in litt. 2000). In 1971-1972, the population was estimated at 800 pairs (Harris 1973). Between 1977 and 1985, it remained more or less stable at around 650 to 850 adults (Harris 1973, Valle 1986, Valle and Coulter 1987). However, during the 1983 El Nio event, the population declined by 50% to 400 birds, but recovered within a season (Valle and Coulter 1987). In 1986, it was estimated at 1,000 adults (Rosenberg et al. 1990). In 1999, a total of 900 individuals was counted during the census (H. Vargas and F. Cruz in litt. 2000). A total of 1,396 cormorants were counted in 2006, which is 10% less than the population counted in 2005. Nevertheless, the total counted in 2006 is one of the four highest counts among all cormorant surveys conducted since 1977. After the last El Nio event of 1997-1998, growth in the cormorant population has been higher than ever before in the survey period (1977-2006). Still, results as of 2003 show a decrease in the rate of population growth and a low percentage of juveniles (3% in 2006), suggesting that the population is stabilizing at a new high (Jimnez-Uzctegui et al. 2007).

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Range

Galapagos Islands (coasts of Fernandina and Isabela).
  • Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2014. The eBird/Clements checklist of birds of the world: Version 6.9. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/

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Range

This unique cormorant is endemic to the Galapagos Islands, Ecuador, where it has a very restricted range. It is found on just two islands; Fernandina, where it is found mainly on the east coast, as well as on the northern and western coasts of Isabela (2). The population has undergone severe fluctuations; the 1983 El Niño event resulted in a 50% reduction of the population to just 400 individuals. The population recovered quickly, however, and was estimated to number 900 individuals in 1999 (2).
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
It usually nests in sheltered areas, on shingle and flat lava outcrops (Levque 1963), mostly within 100 m of the shoreline (Harris 1974). It is thought to breed near the coldest and richest waters (Harris 1974, Valle 1986). It nests in small groups of just a few pairs (Levque 1963), mainly during the colder season (July-October) when marine productivity is highest, and the risk of heat stress to chicks and incubating adults is reduced (Harris 1974). Some pairs may nest biannually (Valle and Coulter 1987). It is highly sedentary (Valle 1986) and fearless of humans (Levque 1963). It preys on eels, octopuses and fish (Jimnez-Uzctegui et al. 2007).


Systems
  • Terrestrial
  • Marine
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This species inhabits the rocky shores of the volcanic islands on which it occurs. It forages in shallow coastal waters, including bays and straits (1) and rarely ventures further than 1km away from the breeding areas (3).
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
VU
Vulnerable

Red List Criteria
D2

Version
3.1

Year Assessed
2013

Assessor/s
BirdLife International

Reviewer/s
Butchart, S.

Contributor/s
Cruz, F., Freile, J., Jimnez-Uzctegui, G., Tye, A., Vargas, H. & Wiedenfeld, D.

Justification
This species qualifies as Vulnerable because it occupies an extremely small range, comprising only two locations, and its status could change in a short space of time, such that it qualifies as Critically Endangered, or even Extinct, owing to potential future threats.


History
  • 2012
    Vulnerable (VU)
  • Vulnerable (VU)
  • Endangered (EN)
  • Endangered (EN)
  • Endangered (EN)
  • Endangered (EN)
  • Endangered (EN)
  • Vulnerable (VU)
  • Vulnerable (VU)
  • Threatened (T)