Hawaiian Endemic Endangered. The remains of fossils indicate that these ducks once lived on the entire archipelago, but now remain only on three small isolated islands.
The name was given by Lionel Walter Rothschild in 1892, the duck was named after the island of Laysan , one of the Northwest Hawaiian islands . It is part of the mallard treasure subfamily of real ducks , is a genetically unusual species with highly developed behavior. Recent evidence indicates that it came from South Asian ducks , the ancestors of mallards in the southern hemisphere, and not from randomly migrating mallards ( Anas platyrhynchos ), as reported in the past.
Lysan Mallard the size of a teal, dark brown, with white circles around the eyes. The beak is short, spade-shaped, dark green with various black spots in males and dull orange with various black spots in females. In some drakes, the head and neck are slightly iridescent and the central feathers of the tail are slightly turned. On the wings of both sexes there is an iridescent purplish-green area (mirror). Paws are orange, usually brighter in drakes. Shedding in the first year of life is complete, birds lose their entire plumage and cannot fly, while new feathers will not grow. Wild ducks survived, as you know, to the age of 12 years, and in captivity - to 18 years.
Laysan mallard walks and runs well, her pelvic girdle is adapted to ground search for food. Energetic feeding behavior includes short runs with on-the-fly fishing for Neoscatella sexnotata flies . With an elongated neck and a closed beak, located near the surface of the earth, ducks run along the edge of the sea, rise like a cloud in flight forward, throw on flies , quickly opening and closing their beak. Ducks also forage on the surface of the water, filtering food in the shallow waters of lakes, the seashore, and among mountain vegetation: invertebrates , algae , leaves and seeds . During the day, especially during the mating season, they prefer to hide among the grass and bushes, avoiding meeting with predators such as frigates . They prefer to leave their shelters and look for food on the lake at sunset, although it seems that from year to year changes are being noted in accordance with their diet.
Pair formation begins in the fall, the nest is built in the spring. The female howls a well-hidden nest on the surface of the earth among dense vegetation, most often among Eragrostis variabilis . The nest has the shape of a shallow bowl, lined with grass, and feathers below. Egg laying usually occurs from April to August. The average clutch size on Laysan Island is 4 eggs . Newly born populations on Midway lay more eggs . Ducklings appear early and feed themselves on the second day after birth, but are guarded, hatched and taken to areas with a brood feed for approximately 40 to 60 days.
The decrease in the number of Lysan mallard began 1000-1600 years ago with the colonization of the Hawaiian Islands by the Polynesians and is associated with mammalian predators that are not characteristic of these islands. By 1860, all ducks disappeared, with the exception of Laysan Island (of the same name as a duck), most likely due to introduced rats . Like many other species isolated on the island, Lysan mallard evolved in the absence of carnivorous mammals , unsuitable for protection from predators such as rats , pigs, and the small Asian mongoose . For example, the Lysan mallard is likely to freeze or take off from fear - a strategy that worked out well to protect against Hawaiian flying predators, but was ineffective against ground ones. Although the non-migratory Lysan mallard can fly, it does not fly between the islands.
The Laysan Mallard took refuge during the 19th century on the rat- free Laysan Island, surviving on the smallest geographical area of distribution among all duck species in the world (415 ha / 1.6 sq. Miles). Laysan Island received federal protection in 1909 with the establishment of the Hawaiian Islands Wildlife Sanctuary. However, the devastation of the island's vegetation by introduced domestic rabbits led the duck in 1912 to the risk of extinction with an all-time low population of 7 adults and 5 young individuals.
After many of the domestic rabbits died of starvation, and the rest were destroyed by biologists in 1923, the ducks began to recover, their population increased by 1950 to approximately 500 individuals. Congress in 1966 decided to conserve the species, and in 1967 the Lysan Mallard was declared an endangered species with federal protection. However, there were population threats such as the severe El Niño drought of 1933 and lack of food, which reduced the number to approximately 100 individuals. Now, the reproduction and survival of birds is closely monitored. In 1998, bird specimens were equipped with unique foot rings or radio transmitters to control breeding and survival, which is typical, only 30% of ducklings on Laysan Island survive to plumage. In 2004, the population grew to approximately 576 ducks .
In October 2004 and 2005, 42 Laysan mallards were relocated to Midway Island National Wildlife Refuge through a joint effort by the United States Geological Union and the Fisheries and Wildlife Service to create a second Lysan mallard population in the wild. Creating a second population reduces the risk of the mallard disappearing as a result of accidental disasters such as drought, hurricane, tsunami, outbreaks of the disease (like bird flu ) and accidental introductions of plants and animals, since it is unlikely that a disaster will hit two islands at the same time.
The second “insurance” Lysan mallard population in Midway has grown rapidly, more than double the size of the first two years (USGS 2006c). In January 2007, 100 ducks from Midway Island returned home to the eastern island. Researchers who observed the population on Midway noted that ducks breed on this island at an earlier age and lay more eggs than on Laysan Island. This suggests that the rich habitat and food available on Midway stimulate ducks' reproductive abilities more, which is optimistic about the successful reintroduction of the population .
The outlook for the future of the Lysan Mallard is optimistic, although the threat to the population remains. The threat lies in the introduction of species that are unusual for the territory, which can change living standards, displace local species and adversely affect nesting sites and food supplies. The death of vegetation can increase sediment deposition in lakes and rivers, which serve as the food supplying habitat. Human activity can affect nesting and breeding sites, therefore, admission to the protected shores of Laysan Island can be carried out only for official or scientific purposes. Debris and debris nailed to the shore by ocean currents could do great harm to the duck . Pesticide containers and oil spills have polluted Lysan in the past. Duck habitats on the island are particularly vulnerable to rising sea levels and weather changes associated with global warming . Even a slight increase in water level can destroy most of the existing duck habitats. The spread of parasites such as the Echinuria uncinata nematode can be extremely fatal, as can the transmission of diseases by migratory waterfowl flying along the Pacific migration route (such as bird flu , bird malaria , cholera , botulism and duck plague ). Environmental disasters such as drought, large storms and tsunamis can devastate populations . An increase in the frequency of serious storms is the expected result of global warming .
The Lysan Duck Recovery Plan was developed by the American Fish and Wildlife Service. The goal of the restoration program is to preserve and restore the species in the near future to the lowest level in the list of endangered species , ultimately to ensure that the population is healthy enough and does not require federal protection under the Endangered Species Act . The emphasis of the restoration plan is on the distribution of the Lysan mallard population in the historical and prehistoric areas of distribution. Creating multiple populations will reduce the risk that catastrophic events will lead to species extinction. Increasing population size will reduce the threat of demographic and environmental contingencies. To achieve this goal, biologists plan to create at least five populations on a collection of predator-free Northwest Hawaiian islands and on a site with controlled predators of the Main Hawaiian Island . This plan includes the movement and placement of fully or half captive-raised birds, using wild source eggs for introduction on Main Hawaiian Island . In addition, the plan requires that the result of gene transfer between wild source populations through long-term movements between islands and island-specific transfer for each population reduce threats and improve habitat quality. If the main criteria of the restoration plan are met, the Lysan mallard can go down the list of endangered species and pass the threat of extinction expected by 2019.
