Brazilian Merganser
Encyclopedia
The Brazilian Merganser, Mergus octosetaceus, is a duck
in the typical merganser
genus.
It is one of the six most threatened
waterfowl
in the world with possibly fewer than 250 birds in the wild and none kept in captivity
. The origin of its name is from its long, sharp-edged beak
that has a great number of teeth-looking edges.
, and a white wing patch is particularly noticeable in flight. It has a long thin jagged black bill with red feet and legs. Although females are smaller with a shorter bill and crest, both sexes are alike in color. The slender ducks range in size from 49 centimeters to 56 centimeters as an adult. Young Brazilian Mergansers are mainly black with white throat and breast.
The Brazilian Mergansers are generally silent birds, but may make barking calls in certain situations. Four calls have been recorded. A harsh krack-krack acts as an alarm call
emitted in flight. Males make a barking dog-like call, females make a harsh rrr-rrrr and the contact call ia a soft rak-rak-rak. Ducklings give a high pitched ik-ik-ik.
Depending on the availability of suitable nesting and feeding sites, Brazilian Merganser pairs occupy permanent territories
of eight to seventeen kilometer stretches of rivers. Tree cavities, rock crevices, or disused burrows predominantly made by armadillo
s are the ideal places for these mergansers to build their nest
s. It is thought the breeding season is during the austral
winter
, when rain is minimal and water levels are low, but it may vary geographically. The Brazilian Merganser usually lays three to six eggs in June and July, with the chicks hatching during the following July and August. The young are capable of flight by September and/or October. Only the female birds incubate
the eggs, but both parents care for the young. This is a very unusual behavior in ducks for both parents to help raise the young birds including direct provision of food to young. Adult Brazilian Mergansers are believed to remain on the same territory all year round, but there is not very much information about their movements and dispersal, so information on this is presently speculative in nature.
Fish
is the Brazilian Merganser main food, and they also eat Mollusks, insects and their larva
e. The birds, usually in pairs, capture fish by diving in river rapid
s and backwater.
for Brazilian Mergansers is believed to be only 250 birds. Originally, the duck's geographical distribution comprised central-south Brazil and adjacent regions in Paraguay
and Argentina
. Currently, all confirmed populations are located in Brazil and a more recent population in Argentina
and information on most populations is very scarce. The Brazilian Merganser population in the Serra da Canastra region is the most significant and best known, with populations occurring hundreds of kilometers away from each other. There are 47 individuals – 28 adults and 19 young – in the Serra de Canastra region as of 2006. Most Mergansers are found in the Serra da Canastra National Park
. 70 birds have been seen near the park's headquarters in rio São Francisco. In Jalapão region are estimated 13 individuals in Novo river on 2009/2010 (four couples and some solitary adults).
In 2002, the species was also found on the Arroyo Uruzu in Misiones, Argentina, the first record in the country for ten years, despite extensive surveys done by local researchers conducted throughout previous years. The bird was last reported seen in 1984 in Paraguay, where very little habitat remains; however some local reports show that a few individuals may still be living in the area.
. Brazilian Mergansers are very territorial birds defending large stretches of river and the land surrounding the fast-flowing water. They are recognized as a resident species that do not abandon the watercourses where it established its territory, which some think is a reason the birds are endangered. They don't move or want to move once their habitats have disappeared. The birds need large territories and their habitat is fast dwindling.
ing of rivers caused by the expansion of farming
activities, mining
, watershed degradation and soil erosion, as well as deforestation
.
Current traditional soil management
and use practices in the region from farming may bring about serious damage regarding conservation of natural resources
, especially water, on which the Brazilian Mergansers and the farmers themselves are dependent. One of the farming practices here is shifting cultivation
. It is common in the region to see farmers burning forest areas causing environmental damage to the natural vegetation and soils and the resident species.
A new threat to the species includes the installation of hydroelectric plants. Hydropower plants are planned to be built in the same rivers that Brazilian Mergansers have been found in Paraná
(rio Tibagi), Goiás
(rio Paranã) and Tocantins
(rio Novo). The hydropower plants are a major threat to the birds' survival because the plants transform systems such as creeks, rivers and streams into turbid lake systems. The project has government backing in spite of the damage it may cause.
Dam-building has also become a major part in the disappearance of these birds. The filling of the Urugua-i reservoir, which took place between 1989 and 1991, had a major impact on Brazilian Mergansers in Argentina. The population declined drastically when its fast-flowing rivers were turned into large lakes. After the Urugua-i dam was built, the birds have only been seen on the Uruzu stream, a tributary of the Urugua-i. The dams flood suitable habitat, especially in Brazil
and Paraguay
, where the Brazilian Mergansers build their nests and lay their eggs.
Another threat to the Brazilian Merganser is tourism
. The scenic beauty of Serra de Canastra National Park brings people from around the world to see the ecotourism
landmark. Tourists are attracted to the abundant supply of clear water with over 150 waterfalls in the area. Sporting activities also create a disturbance for the Brazilian Mergansers. Activities such as canoeing
and rafting
disturb the natural habitats for the Brazilian Mergansers that thrive on the rapid-rivers. With the activities being haphazardly practiced and the increasing amount of facilities being built on the margin of the rivers, they may cause serious threats to the Brazilian Mergansers populations. It disturbs the area of use and their breeding patterns and its habitat due to water course pollution and deforestation.
Other threats include inbreeding
, pesticides and predation
. Very few individuals survive from these threats and extinction may be imminent. People hunting the birds for food and collecting them for exhibition specimens contributed to the decline of the species.
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
in the typical merganser
Mergus
Mergus is the genus of the typical mergansers, fish-eating ducks in the seaduck subfamily . The Hooded Merganser, often termed Mergus cucullatus, is not of this genus but closely related...
genus.
It is one of the six most threatened
Threatened species
Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...
waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
in the world with possibly fewer than 250 birds in the wild and none kept in captivity
Captivity (animal)
Animals that live under human care are in captivity. Captivity can be used as a generalizing term to describe the keeping of either domesticated animals or wild animals. This may include for example farms, private homes and zoos...
. The origin of its name is from its long, sharp-edged beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
that has a great number of teeth-looking edges.
Description
This merganser is a dark, slender duck with a shiny dark-green hood with a long crest, which is usually shorter and more worn-looking in females. Upperparts are dark grey while the breast is light grey, getting paler toward the whitish bellyAbdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
, and a white wing patch is particularly noticeable in flight. It has a long thin jagged black bill with red feet and legs. Although females are smaller with a shorter bill and crest, both sexes are alike in color. The slender ducks range in size from 49 centimeters to 56 centimeters as an adult. Young Brazilian Mergansers are mainly black with white throat and breast.
The Brazilian Mergansers are generally silent birds, but may make barking calls in certain situations. Four calls have been recorded. A harsh krack-krack acts as an alarm call
Alarm Call
"Alarm Call" is a song by Björk released as the fourth single from her third studio album Homogenic, peaking at #33 in the UK.-Background:...
emitted in flight. Males make a barking dog-like call, females make a harsh rrr-rrrr and the contact call ia a soft rak-rak-rak. Ducklings give a high pitched ik-ik-ik.
Breeding
Depending on the availability of suitable nesting and feeding sites, Brazilian Merganser pairs occupy permanent territories
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...
of eight to seventeen kilometer stretches of rivers. Tree cavities, rock crevices, or disused burrows predominantly made by armadillo
Armadillo
Armadillos are New World placental mammals, known for having a leathery armor shell. Dasypodidae is the only surviving family in the order Cingulata, part of the superorder Xenarthra along with the anteaters and sloths. The word armadillo is Spanish for "little armored one"...
s are the ideal places for these mergansers to build their nest
Bird nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...
s. It is thought the breeding season is during the austral
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
winter
Winter
Winter is the coldest season of the year in temperate climates, between autumn and spring. At the winter solstice, the days are shortest and the nights are longest, with days lengthening as the season progresses after the solstice.-Meteorology:...
, when rain is minimal and water levels are low, but it may vary geographically. The Brazilian Merganser usually lays three to six eggs in June and July, with the chicks hatching during the following July and August. The young are capable of flight by September and/or October. Only the female birds incubate
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
the eggs, but both parents care for the young. This is a very unusual behavior in ducks for both parents to help raise the young birds including direct provision of food to young. Adult Brazilian Mergansers are believed to remain on the same territory all year round, but there is not very much information about their movements and dispersal, so information on this is presently speculative in nature.
Fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
is the Brazilian Merganser main food, and they also eat Mollusks, insects and their larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e. The birds, usually in pairs, capture fish by diving in river rapid
Rapid
A rapid is a section of a river where the river bed has a relatively steep gradient causing an increase in water velocity and turbulence. A rapid is a hydrological feature between a run and a cascade. A rapid is characterised by the river becoming shallower and having some rocks exposed above the...
s and backwater.
Population
The total world populationPopulation
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
for Brazilian Mergansers is believed to be only 250 birds. Originally, the duck's geographical distribution comprised central-south Brazil and adjacent regions in Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
and Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. Currently, all confirmed populations are located in Brazil and a more recent population in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
and information on most populations is very scarce. The Brazilian Merganser population in the Serra da Canastra region is the most significant and best known, with populations occurring hundreds of kilometers away from each other. There are 47 individuals – 28 adults and 19 young – in the Serra de Canastra region as of 2006. Most Mergansers are found in the Serra da Canastra National Park
Serra da Canastra National Park
The Serra da Canastra National Park is located in Minas Gerais state, Brazil, between 20º00’—20º30’ S and 46º15’—47º00’ W.-External links:** *...
. 70 birds have been seen near the park's headquarters in rio São Francisco. In Jalapão region are estimated 13 individuals in Novo river on 2009/2010 (four couples and some solitary adults).
In 2002, the species was also found on the Arroyo Uruzu in Misiones, Argentina, the first record in the country for ten years, despite extensive surveys done by local researchers conducted throughout previous years. The bird was last reported seen in 1984 in Paraguay, where very little habitat remains; however some local reports show that a few individuals may still be living in the area.
Habitat
The slender Brazilian Mergansers live in low densities in remote and mountainous regions where it inhabits clean rivers and streams with river rapids and riparian vegetationRiparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by...
. Brazilian Mergansers are very territorial birds defending large stretches of river and the land surrounding the fast-flowing water. They are recognized as a resident species that do not abandon the watercourses where it established its territory, which some think is a reason the birds are endangered. They don't move or want to move once their habitats have disappeared. The birds need large territories and their habitat is fast dwindling.
Threat
The Brazilian Mergansers are very sensitive to habitat degradation and loss primarily due to human actions. A major threat to the birds' survival is the issue of siltSilt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
ing of rivers caused by the expansion of farming
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
activities, mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
, watershed degradation and soil erosion, as well as deforestation
Deforestation
Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
.
Current traditional soil management
Soil management
Soil management concerns all operations, practices and treatments used to protect soil and enhance its performance.-Practices:Soil management practices that affect soil quality:...
and use practices in the region from farming may bring about serious damage regarding conservation of natural resources
Natural Resources
Natural Resources is a soul album released by Motown girl group Martha Reeves and the Vandellas in 1970 on the Gordy label. The album is significant for the Vietnam War ballad "I Should Be Proud" and the slow jam, "Love Guess Who"...
, especially water, on which the Brazilian Mergansers and the farmers themselves are dependent. One of the farming practices here is shifting cultivation
Shifting cultivation
Shifting cultivation is an agricultural system in which plots of land are cultivated temporarily, then abandoned. This system often involves clearing of a piece of land followed by several years of wood harvesting or farming, until the soil loses fertility...
. It is common in the region to see farmers burning forest areas causing environmental damage to the natural vegetation and soils and the resident species.
A new threat to the species includes the installation of hydroelectric plants. Hydropower plants are planned to be built in the same rivers that Brazilian Mergansers have been found in Paraná
Paraná (state)
Paraná is one of the states of Brazil, located in the South of the country, bordered on the north by São Paulo state, on the east by the Atlantic Ocean, on the south by Santa Catarina state and the Misiones Province of Argentina, and on the west by Mato Grosso do Sul and the republic of Paraguay,...
(rio Tibagi), Goiás
Goiás
Goiás is a state of Brazil, located in the central part of the country. The name Goiás comes from the name of an indigenous community...
(rio Paranã) and Tocantins
Tocantins (state)
Tocantins is one of the states of Brazil. . The state was formed in 1988 out of the northern part of Goiás, and construction began on the capital, Palmas, in 1989, in contrast to most of the other cities in the state which date back to the Portuguese colonial period...
(rio Novo). The hydropower plants are a major threat to the birds' survival because the plants transform systems such as creeks, rivers and streams into turbid lake systems. The project has government backing in spite of the damage it may cause.
Dam-building has also become a major part in the disappearance of these birds. The filling of the Urugua-i reservoir, which took place between 1989 and 1991, had a major impact on Brazilian Mergansers in Argentina. The population declined drastically when its fast-flowing rivers were turned into large lakes. After the Urugua-i dam was built, the birds have only been seen on the Uruzu stream, a tributary of the Urugua-i. The dams flood suitable habitat, especially in Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
and Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
, where the Brazilian Mergansers build their nests and lay their eggs.
Another threat to the Brazilian Merganser is tourism
Tourism
Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism has become a...
. The scenic beauty of Serra de Canastra National Park brings people from around the world to see the ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...
landmark. Tourists are attracted to the abundant supply of clear water with over 150 waterfalls in the area. Sporting activities also create a disturbance for the Brazilian Mergansers. Activities such as canoeing
Canoeing
Canoeing is an outdoor activity that involves a special kind of canoe.Open canoes may be 'poled' , sailed, 'lined and tracked' or even 'gunnel-bobbed'....
and rafting
Rafting
Rafting or white water rafting is a challenging recreational outdoor activity using an inflatable raft to navigate a river or other bodies of water. This is usually done on white water or different degrees of rough water, in order to thrill and excite the raft passengers. The development of this...
disturb the natural habitats for the Brazilian Mergansers that thrive on the rapid-rivers. With the activities being haphazardly practiced and the increasing amount of facilities being built on the margin of the rivers, they may cause serious threats to the Brazilian Mergansers populations. It disturbs the area of use and their breeding patterns and its habitat due to water course pollution and deforestation.
Other threats include inbreeding
Inbreeding
Inbreeding is the reproduction from the mating of two genetically related parents. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is...
, pesticides and predation
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
. Very few individuals survive from these threats and extinction may be imminent. People hunting the birds for food and collecting them for exhibition specimens contributed to the decline of the species.