Galapagos cormorants (Phalacrocorax harrisi) produce little fat that keeps feathers from getting wet. Therefore, after leaving the water, the birds are forced to spend a lot of time in the sun, drying their plumage.
Charlesjsharp / Wikimedia Commons
American and Chilean biologists have figured out how the Galapagos flightless cormorant lost its ability to fly. In representatives of this species, the functions of proteins that regulate the growth or function of cilia (cilia are important cellular organelles) have changed, and the absence or poor functioning of cilia can affect bone growth. Research published in Science.
Cormorants (Phalacrocorax) - waterfowl the size of a duck or a goose that live in colonies in coastal areas. Now there are about 40 species of cormorants on the planet, the only flightless of them is the Galapagos cormorant (Phalacrocorax harrisi). Their wings are shorter than those of other species, and the ribcage is flatter. At the same time, phylogenetic studies have shown that, unlike penguins and ratites (ostriches, rhea, kiwi), which lost their ability to fly about 50 million years ago, Galapagos cormorants “lost” most of their wings about two million years ago, by evolutionary standards recently ... Therefore, according to scientists, with a fresh example P. Harrisi you can study how birds lose their ability to fly.
The average wing length of the Galapagos flightless cormorant (P.harrisi) - about 19 centimeters with an average body weight of about 3.6 kilograms, and its closest relative, the eared cormorant (P. auritus), has an average wing length of 31.5 centimeters with a body weight of 2.2 kilograms.
A. Burga et al. / Science, 2017
It turned out that P.Harrisi mutations appeared in the genes Ofd1, Evc, Wdr34 and Ift122, which encode proteins that regulate the growth and proper functioning of primary cilia (from the Latin "cilium" - "cilium"). These are organelles that are found in most eukaryotic cells and serve as a sensitive "antenna" coordinating many signaling pathways in the cell. They also play a key role during the embryonic development of vertebrates. In humans, mutations in the genes of these proteins lead to the appearance of rare diseases from the group of skeletal ciliopathies, which lead, among other things, to a decrease in the length of the bones of the arms and ribs. In addition, the authors of the work found a mutation in the CUX1 gene, which also affects the production of proteins that regulate the growth of cilia. This gene is conserved in birds and mammals; it is known to regulate limb growth in chickens. The authors of the work believe that it was the above-described changes in genes that ultimately led to the fact that this species of cormorants lost the ability to fly.
Galapagos flightless cormorant (Phalacrocorax harrisi) inhabits only two islands of the Galapagos archipelago, Fernandina and Isabela. It is the largest representative of the cormorant genus, with a body length of 90-100 centimeters and a mass of 2.5-5 kilograms. Moreover, its wings reach about a third of the length that would be necessary for a bird of this size to fly.Probably, the Galapagos cormorant forgot how to fly, since he did not need to migrate: he was provided with food and had no natural enemies. Perhaps the loss of the ability to fly was an advantage: because of the shortened wings, the buoyancy of the cormorants decreased, so it became easier for them to dive and hunt for fish.
Galapagos Dergach is a small (15 cm) almost wingless land, a living bird. It has dark plumage, black in general, with a more gray head and chest and white patches on the back. It has a scarlet eye, black beak, and short, almost useless wings. They are highly vocal with a wide range of requirements.
The Galapagos Dergach lives in damp fields and a forest hiding in deep cover. In the Galapagos, these habitats are usually found on islands with higher elevations (especially the islands of Santiago, Santa Cruz, and the Negra Mountain Range), and rails are the most common above. They feed on invertebrates, mainly snails, isopods, dragonflies, beetles, ants, also taking berries and some seeds. They feed during the day, passing the ground, throwing leaves and scooping up leaf litter.
Galapagos dergats and people
The Galapagos Dergach, despite being an almost wingless island living by rail, has managed to survive the arrival of humans in the Galapagos. It is a gullible species that is curious about humans and will approach and research them, this naivety makes it vulnerable to feral cats, dogs and pigs. The presented goats and cattle also cause habitat loss, which is causing their numbers to decline.The removal of goats and cattle and the resulting regeneration of trees, bushes and grasses, results in a quick return of the rail. As most of the Galapagos habitat is in the national park and efforts are underway to remove introduced species causing most of the harm, the future looks better for these birds.
- Taylor, B. (1998) rails, guide to rails, ders, gallinules and coots of the world, Yale University Press, ISBN 978-0-300-07758-2