Flightless Cormorant

Detail about Flightless Cormorant:

One bird that many Galapagos visitors hope to catch sight of is the Galapagos flightless cormorant. The Flightless Cormorant is particularly intriguing due to its lack of hability to fly, which is rather unusual among bird species. Indeed, there are 29 species of cormorants, and the Galapagos Cormorant is the only one that is flightless. This means that the species does not migrate and can be seen all year around in the Galapagos Islands. The bird is endemic to the Galapagos, and there are believed to be approximately 1,000 breeding pairs distributed between the two islands.
In 2017 an interesting study was published which attempted to explain why the Galapagos cormorant cannot fly. It was demonstrated that the bird has a number of genetic anomalies which are in common with people that have rare skeletal problems. In humans that have these issues, skulls are misshapen, Rib cages are small, and limbs are typically short. This allowed the researchers to see a link with Galapagos cormorants, which have a very small sternum and short wings. These scientists therefore suggested that a gene mutation was responsible for leaving the Galapagos cormorant flightless. Other studies suggest that because the bird had so few land predators it did not need to fly. It is also proposed as part of this theory that those that were good swimmers were better at passing on their genes.

Description:

Like all cormorants, this bird has webbed feet and sturdy legs that propel it through the water as it seeks its prey of fish, small octopuses, and other little marine creatures. The species feeds near the sea floor and no more than 200 metres offshore.The flightless cormorant is the largest extant member of its family, 89–100 cm (35–39.5 in) in length and weighing 2.5–5.0 kg (5.5–11.0 lb), and its wings are about one-third the size that would be required for a bird of its proportions to fly. The keel on the breastbone, where birds attach the large muscles needed for flight, is also significantly reduced.

The flightless cormorants look slightly like a duck, except for their short, stubby wings. The upperparts are blackish, and the underparts are brown. The long beak is hooked at the tip and the eye is turquoise. Like all members of the cormorant family, all four toes are joined by webbed skin. Males and females are similar in appearance, although males are larger and ca. 35% heavier. Juveniles are generally related to adults but differ in that they are glossy black in colour with a dark eye. Adults produce low growling vocalizations.

Like other cormorants, this bird's feathers are not waterproof, and they spend time after each dive drying their small wings in the sunlight. Their flight and contour feathers are much like those of other cormorants, but their body feathers are much thicker, softer, denser, and more hair-like. They produce very little oil from their preen gland; it is the air trapped in the dense plumage that prevents them from becoming waterlogged.

Distribution and habitat:

This unique cormorant is endemic to the Galapagos Islands, Educator, where it has a very restricted range. It is found on just two islands; Fernandina, and the northern and western coasts of Isabela. Distribution associates with the seasonal upwelling of the eastward flowing Equatorial Undercurrent (or Cromwell Current) which provides cold nutrient rich water to these western islands of the archipelago. The population has undergone severe fluctuations; the 1983 an El Niño-Southern Oscillation (ENSO) 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 by 1999.

This species inhabits the rocky shores of the volcanic islands on which it occurs. It forages in shallow coastal waters, including bays and straits. Flightless cormorants are extremely sedentary, remaining most or all of their lives, and breeding, on local stretches of coast-line several hundred metres long. Their sedentary nature is reflected in a genetic differentiation between the main colonies, and particularly between Fernandina and Isabela Island.

Ecology:

Nesting tends to take place during April–October, when sea surface temperatures are coldest resulting in an abundance of marine food, and the risk of heat stress to the chicks is decreased. At this time, breeding colonies consisting of up to about 12 pairs form. The courtship behavior 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. Items of seaweed are brought predominantly by the male and gifted to the female to be woven into a bulky nest, just above high water mark.

The female generally lays three whitish eggs per clutch, though usually only one chick survives. Both male and female share equally in incubation. Once the eggs have hatched, both parents continue to share responsibilities of brooding and feeding the offspring, although the female provides 40-50% more food items than her partner. As the chicks approach independence at 70 days old and if food supplies are plentiful, the female will desert the offspring leaving the male to carry out further parenting, and she will re-partner and breed with a new mate. Thus, females, but not males, can raise several broods in a single season, although studies over a decade indicate that environmental conditions allowing sufficient food availability for this, occur infrequently.

Conservation:

The flightless cormorant is one of the world's rarest birds. A survey carried out by the Charles Darwin Research Station in 2004 indicated that the species has a population of about 1,500 individuals. In 2009, Birdlife International set the number of individuals of the flightless cormorant at only 900 individuals, although a more recent estimate in 2011 was 1679 individuals. It was formerly classified as Endangered by the IUCN, but recent research shows that it is not as rare as previously believed and that its population has stabilized. Consequently, it was downlisted to Vulnerable in 2011.

All populations of this species are found within the Galapagos National Park and Marine Reserve; furthermore, the archipelago was designated as a World Heritage Site in 1978. The Charles Darwin Research Station has monitored the species regularly to keep track of fluctuations in numbers over time. Conservation proposals include the continuation of annual monitoring programs, restriction on human visitation within the species range, and the prevention of fishing with nets in the bird's foraging range.

Flightless Cormorant Video: