The only cormorant species that cannot fly, the flightless cormorant is a unique bird endemic to the Galapagos Islands.
What Does It Look Like?
Flightless cormorants look similar to their cormorant relatives, including common North American species like double-crested or Brandt’s cormorants, only with stubby little wings that render them flightless.
According to the Galapagos Conservation Trust, their stunted wings are just a third of the size they would need to be to fly, though they help with balance as the birds hop between rocks.
These flightless birds are a mixture of dull brown and black colors. Like other cormorants, they have webbed feet and hooked bills.
Range and Habitat
Flightless cormorants live only in the Galapagos Islands, where according to the Galapagos Conservation Trust, they are most common on the northwestern coast of Isabela Island and the east coast of Fernandina Island, two of the largest and westernmost islands in the archipelago.
They inhabit the island’s shores, where they can be seen moving from rock to rock or drying their wings from a swim through the coastal waters in search of food.
Migration
Since they can’t fly, these birds don’t migrate.
What Does It Eat?
Flightless cormorants are strong swimmers, a skill they use to dive deep underwater to catch fish, eels, and octopuses.
As you can see from the video, cormorants use their hind legs to kick themselves down through the water to rocks on the ocean floor where they can pick off fish or other prey.
How Big Is It?
The heaviest member of the cormorant family, flightless cormorants generally weigh about six pounds and stand about three feet tall.
If you were to travel to the Galapagos Islands and see one in the wild, it likely wouldn’t appear too much taller than North American cormorants like the double-crested cormorant, which has a typical length of 27.6 to 35.4 inches, according to the Cornell Lab of Ornithology’s All About Birds.
What Does It Sound Like?
This species won’t win any awards for the world’s most melodious sounds, featuring a throaty display call.
How Long Does It Live?
Flightless cormorants can grow to be quite old birds.
The Galapagos Conservation Trust states that while they do face some predation from snakes, owls, hawks, and sharks, they can live for up to 50 years.
Conservation Status
According to the Galapagos Conservation Trust, there are about 1,000 breeding pairs of flightless cormorants on the Galapagos Islands of Isabela and Fernandina, where they are most common.
The IUCN Red List assessed the flightless cormorant as “vulnerable” in 2018.
Due to their lack of flight and limited range, they are vulnerable to environmental changes, as the GCT reports half the population was lost in 1983 in a severe El Niño event.
Future El Niño events, oil spills, or volcanic eruptions have the potential to cause serious declines in flightless cormorant populations.
Why Did the Flightless Cormorant Lose Its Ability to Fly?
According to a UCLA study, birds may lose their ability to fly for two reasons.
One is they don’t need to fly to migrate or escape predators, which can allow mutations to “gradually accumulate in the gene pool,” and the other is called positive selection, where not being able to fly improves something else, such as being strong swimmers, a skill that flightless cormorants rely on to find food.
According to the UCLA study, released in 2017, Galapagos cormorants displayed a mutation in the CUX1 gene, previously linked to shortened wings in chickens, as well as genetic mutations affecting cilia, small, hair-like structures that play an important role in bone growth.