Flying Steamer Duck
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The flying steamer duck (''Tachyeres patachonicus''), also known as the flying steamer-duck or flying steamerduck, is a species of South American duck in the family
Anatidae The Anatidae are the biological family (biology), family of water birds that includes ducks, goose, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted f ...
.


Taxonomy and Systematics

The flying steamer duck is one of four steamer ducks, in the genus ''Tachyeres'', which also includes the Fuegian steamer duck (''Tachyeres pteneres''), the Chubut steamer duck (''Tachyeres leucocephalus''), and the Falkland steamer duck (''Tachyeres brachypterus''). The steamer ducks are named for their method of mobility, as the manner in which they use wings and feet to paddle across the water resembles an old-time steam boat. The steamer ducks are members of the Southern Hemisphere shelducks clade
Tadorninae The Tadornini is a biological tribe that includes the shelducks and sheldgeese, which is placed in subfamily Anatinae of family Anatinae, which includes the ducks and most duck-like waterfowl such as the geese and swans. It has been treated a ...
. The three flightless species are monophyletic, with the flying steamer ducks splitting off phylogenetically. It is the only steamer duck which can fly, and the only one to occur on inland fresh waters. However, some individual male flying steamer ducks within the species are incapable of flight due to excessive size and
wing loading In aerodynamics, wing loading is the total weight of an aircraft or flying animal divided by the area of its wing. The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading. The faster an airc ...
s.


Description

Though they are the smallest of the four ''Tachyeres'' species, flying steamer ducks share similar plumage traits with other steamer ducks including brown head and neck feathers with white stripes stretching from their eyes to the napes of their necks, and brown-gray gradient body feathers. Their underbellies are mostly white, and their feet are orange. Female flying steamer ducks have smaller bills relative to males that are orange with black tips, while males have darker gray bills with slight yellow accents. Flying steamer ducks are also
sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
to the extent that males are heavier but have smaller cranial elements and wingspans than females. Males and females both possess cornified orange carpal knobs on the proximal part of the carpometacarpus bone, and these knobs are used in display as well as interspecies and intraspecies combat by males. Sexual dimorphism can also be observed in the duration and pitch of their various calls, which sound much like grunts. The females’ grunts have been described as lower pitched than the males’ grunts, and usually occur in rapid succession of similar pitch. Males have three distinct grunts that have been described as whistle-like, including a ‘rasping’ grunt, a ‘ticking’ grunt, and a ‘sibilant’ grunt. Flying steamer ducks undergo three molts per annual cycle, and these molts vary widely with geographic location. The wear and degradation on the primary and secondary feathers of observed flying steamer ducks varies depending on the location and flight behavior of the individuals.


Distribution and Habitat

Flying steamer ducks inhabit aquatic areas at the southern tip of South America, specifically
Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
and
Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
,
Tierra del Fuego Tierra del Fuego (, ; Spanish for "Land of Fire", rarely also Fireland in English) is an archipelago off the southernmost tip of the South America, South American mainland, across the Strait of Magellan. The archipelago consists of the main is ...
, and the
Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Dub ...
. Genetic comparisons of Falkland Island steamer ducks suggest the species diverged from continental steamer duck species between 2.2 and 2.6 million years ago, coinciding with a proposed land bridge that may have once connected the Falkland Islands to the mainland. The three steamer duck species that inhabit the mainland share a common ancestor roughly 15,000 years ago, and the species show genetic differentiation as well as different stages between flightless-ness and flying ability. For this reason, steamer ducks have been praised as an excellent potential genus for studying the evolution of flightless-ness in birds. Flying steamer ducks are widely distributed compared to other steamer duck species, likely due to their flying ability, and have been observed to reside in both freshwater and marine environments throughout Chile, Argentina, and the Falkland Islands.


Behavior and Ecology


Breeding

Little is known about the breeding rituals of flying steamer ducks. They are thought to be mostly monogamous and spend much of their time together in pairs. They engage in highly ritualized mating, in which the male and female begin by dipping their bills into the water at increasingly fast paces before the female submerges almost completely into the water and is mounted by the male, after which the female and male raise their bills high into the air in a hostile fashion and grunt audibly.


Food and Feeding

Both flightless and flying steamer ducks engage in foraging behaviors with interspecific and intersexual differences. Flying steamer ducks have almost exclusively been observed to forage in pairs, preferring to dive either around deep-water kelp beds or around shallow water zones. Males and females do not show consistencies among pairs in terms of who is the first to dive, but within pairs the first to dive is consistent in all observed diving instances. Flying steamer ducks share dietary preferences with other steamer duck species and have been reported to feed on
mollusks Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The num ...
and
crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...
s as well as other marine invertebrates, but little is known about the precise species that steamer ducks prey on.


Threats

Both flying steamer ducks and flightless steamer ducks experience nest predation by various avian and mammalian predators, including Chimango Caracaras, *
Crested Caracara The crested caracara (''Caracara plancus'') is a bird of prey (raptor) in the falcon Family (biology), family, Falconidae. It was formerly placed in the genus ''Polyborus'' before being given in its own genus, ''Caracara (genus), Caracara''. It i ...
s, the Fuegian Culpeo Fox, and the introduced
American mink The American mink (''Neogale vison'') is a semiaquatic species of Mustelidae, mustelid native to North America, though human introduction has expanded its range to many parts of Europe, Asia, and South America. Because of range expansion, the Am ...
Besides nest predators, flying steamer ducks are threatened only by competition for resources. Both the males and females are notoriously pugnacious and have been described as intensely territorial and often unnecessarily aggressive towards other individuals and other species, regardless of whether or not that species poses a threat to or lives in competition with the flying steamer ducks. Flying steamer ducks have been observed to target entire flocks of Silvery grebes and Hooded grebes and have also been observed to kill Red shovelers for seemingly no apparent reason. Male flying steamer ducks attack by grabbing their opponents by the neck and hitting their opponents on the head, neck or body using their carpal wing knobs.


Status

The flying steamer ducks are not an endangered species and are categorized as a
Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...
species, however increased nest predation of flightless steamer duck nests by American minks was reported to be a potential future threat to duck populations in Tierra del Fuego wildlife areas.


References

{{Authority control flying steamer duck Birds of Patagonia Birds of the Falkland Islands Birds of islands of the Atlantic Ocean flying steamer duck flying steamer duck Birds of subantarctic islands