Mottled Duck
Encyclopedia
The Mottled Duck
or Mottled Mallard is a medium-sized dabbling duck. It is intermediate in appearance between the female Mallard
and the American Black Duck
. It is closely related to those species
, and is sometimes considered a subspecies
of the former, but this is inappropriate (see systematics).
There are two distinct populations of Mottled Ducks. One population, A. fulvigula maculosa (Mottled Duck), lives on the Gulf of Mexico
coast between Alabama
and Tamaulipas
(Mexico
); outside the breeding season individual birds may venture as far south as to Veracruz
. The other, A. fulvigula fulvigula (Florida Duck), is resident in central and south Florida
and occasionally strays north to Georgia
. The same disjunct distribution pattern was also historically found in the local Sandhill Crane
s.
Along the Gulf of Mexico coast, the Mottled Duck is one of the most frequently banded waterfowl. This is due in part to the fact that it is mostly non-migratory. Approximately one out of every twenty mottled ducks is banded, making it an extremely prized and sought after bird among hunters.
(wing patch), which is not bordered with white as with the Mallard
. Males and females are similar, but the male's bill is bright yellow, whereas the female's is deep to pale orange, occasionally lined with black splotches around the edges and near the base.
The plumage is darker than in female Mallards, especially at the tail, and the bill is yellower. In flight, the lack of a white border to the speculum is a key difference. The American Black Duck
is darker than most Mottled Ducks, and its wing-patch is more purple than blue. The behaviour and voice are the same as the Mallard.
Mottled Ducks feed by dabbling in shallow water, and grazing on land. They mainly eat plants, but also some mollusks and aquatic insects. The ducks are fairly common within their restricted range; they are resident all-year round and do not migrate
. The breeding habitat is coastal marshes. The nest is built on the ground amongst vegetation, such as bull-rush and marsh grass.
n population, which occurs approximately south of Tampa
, is separated as the nominate subspecies Anas fulvigula fulvigula and is occasionally called the Florida Duck or Florida Mallard.)
by being somewhat lighter in color and less heavily marked; while both subspecies are intermediate between female Mallards and American Black Ducks, the Florida Mottled Duck is closer to the former and the Mottled Duck closer to the latter in appearance; this is mainly recognizable in the lighter head being quite clearly separated from the darker breast in Mottled, but much less so in Florida Mottled Ducks. As the subspecies' ranges do not overlap, these birds can only be confused with female Mallards and American Black Ducks however; particularly female American Black Ducks are often only reliably separable by their dark purple speculum from Mottled Ducks in the field.
mtDNA control region sequence
data indicates that these birds are derived from ancestral American Black Ducks, being far more distantly related to the Mallard, and that the subspecies, as a consequence of their rather limited range and sedentary habits, are genetically well distinct already (McCracken et al. 2001).
As in all members of the "mallardine" clade
of ducks, they are able to produce fertile hybrids with their close relatives, the American Black Duck and the Mallard. This has always been so to a limited extent; individuals of the migratory American Black ducks which winter in the Mottled Duck's range may occasionally stay there and mate with the resident species, and for the Mallard, which colonized North America
later, the same holds true (McCracken et al. 2001).
While the resultant gene flow
is presently no cause for concern,
habitat
destruction and excessive hunting could eventually reduce this species to the point where the hybridization with mallards would threaten to make it disappear as a distinct taxon
(Rhymer & Simberloff 1996). This especially applies to the Florida Duck (Mazourek & Gray 1994), in the fairly small range of which rampant habitat destruction due to urbanization
and draining of wetlands has taken place in the last decades; this in combination with climate change
affecting the Everglades
could be sufficient to cause the Florida Duck to decline to a point where hunting would have to be restricted or prohibited (McCracken et al. 2001). At present, these birds too appear to be holding their own with a population of 50.000-70.000 individuals (BirdLife International 2004).
or Mottled Mallard is a medium-sized dabbling duck. It is intermediate in appearance between the female Mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
and the American Black Duck
American Black Duck
The American Black Duck is a large dabbling duck. American Black Ducks are similar to Mallards in size, and resemble the female Mallard in coloration, although the Black Duck's plumage is darker...
. It is closely related to those species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, and is sometimes considered a subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the former, but this is inappropriate (see systematics).
There are two distinct populations of Mottled Ducks. One population, A. fulvigula maculosa (Mottled Duck), lives on the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
coast between Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...
and Tamaulipas
Tamaulipas
Tamaulipas officially Estado Libre y Soberano de Tamaulipas is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 43 municipalities and its capital city is Ciudad Victoria. The capital city was named after Guadalupe Victoria, the...
(Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
); outside the breeding season individual birds may venture as far south as to Veracruz
Veracruz
Veracruz, formally Veracruz de Ignacio de la Llave officially Estado Libre y Soberano de Veracruz de Ignacio de la Llave , is one of the 31 states that, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided in 212 municipalities and its capital city is...
. The other, A. fulvigula fulvigula (Florida Duck), is resident in central and south Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and occasionally strays north to Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
. The same disjunct distribution pattern was also historically found in the local Sandhill Crane
Sandhill Crane
The Sandhill Crane is a large crane of North America and extreme northeastern Siberia. The common name of this bird references habitat like that at the Platte River, on the edge of Nebraska's Sandhills in the American Midwest...
s.
Along the Gulf of Mexico coast, the Mottled Duck is one of the most frequently banded waterfowl. This is due in part to the fact that it is mostly non-migratory. Approximately one out of every twenty mottled ducks is banded, making it an extremely prized and sought after bird among hunters.
Description
The adult Mottled Duck is 44 to 61 cm (17.3 to 24 in) long from head to tail. It has a dark body, lighter head and neck, orange legs and dark eyes. Both sexes have a shiny green-blue speculumSpeculum feathers
The speculum is a patch, often distinctly coloured, on the inner remiges of some birds.Examples of the colour of the speculum in a number of ducks are:* Common Teal and Green-winged Teal: Iridescent green edged with buff....
(wing patch), which is not bordered with white as with the Mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
. Males and females are similar, but the male's bill is bright yellow, whereas the female's is deep to pale orange, occasionally lined with black splotches around the edges and near the base.
The plumage is darker than in female Mallards, especially at the tail, and the bill is yellower. In flight, the lack of a white border to the speculum is a key difference. The American Black Duck
American Black Duck
The American Black Duck is a large dabbling duck. American Black Ducks are similar to Mallards in size, and resemble the female Mallard in coloration, although the Black Duck's plumage is darker...
is darker than most Mottled Ducks, and its wing-patch is more purple than blue. The behaviour and voice are the same as the Mallard.
Mottled Ducks feed by dabbling in shallow water, and grazing on land. They mainly eat plants, but also some mollusks and aquatic insects. The ducks are fairly common within their restricted range; they are resident all-year round and do not migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
. The breeding habitat is coastal marshes. The nest is built on the ground amongst vegetation, such as bull-rush and marsh grass.
Systematics
The FloridaFlorida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
n population, which occurs approximately south of Tampa
Tâmpa
Tâmpa may refer to several villages in Romania:* Tâmpa, a village in Băcia Commune, Hunedoara County* Tâmpa, a village in Miercurea Nirajului, Mureş County* Tâmpa, a mountain in Braşov city...
, is separated as the nominate subspecies Anas fulvigula fulvigula and is occasionally called the Florida Duck or Florida Mallard.)
by being somewhat lighter in color and less heavily marked; while both subspecies are intermediate between female Mallards and American Black Ducks, the Florida Mottled Duck is closer to the former and the Mottled Duck closer to the latter in appearance; this is mainly recognizable in the lighter head being quite clearly separated from the darker breast in Mottled, but much less so in Florida Mottled Ducks. As the subspecies' ranges do not overlap, these birds can only be confused with female Mallards and American Black Ducks however; particularly female American Black Ducks are often only reliably separable by their dark purple speculum from Mottled Ducks in the field.
mtDNA control region sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
data indicates that these birds are derived from ancestral American Black Ducks, being far more distantly related to the Mallard, and that the subspecies, as a consequence of their rather limited range and sedentary habits, are genetically well distinct already (McCracken et al. 2001).
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of ducks, they are able to produce fertile hybrids with their close relatives, the American Black Duck and the Mallard. This has always been so to a limited extent; individuals of the migratory American Black ducks which winter in the Mottled Duck's range may occasionally stay there and mate with the resident species, and for the Mallard, which colonized North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
later, the same holds true (McCracken et al. 2001).
While the resultant gene flow
Gene flow
In population genetics, gene flow is the transfer of alleles of genes from one population to another.Migration into or out of a population may be responsible for a marked change in allele frequencies...
is presently no cause for concern,
habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
destruction and excessive hunting could eventually reduce this species to the point where the hybridization with mallards would threaten to make it disappear as a distinct taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
(Rhymer & Simberloff 1996). This especially applies to the Florida Duck (Mazourek & Gray 1994), in the fairly small range of which rampant habitat destruction due to urbanization
Urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....
and draining of wetlands has taken place in the last decades; this in combination with climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
affecting the Everglades
Everglades
The Everglades are subtropical wetlands in the southern portion of the U.S. state of Florida, comprising the southern half of a large watershed. The system begins near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee...
could be sufficient to cause the Florida Duck to decline to a point where hunting would have to be restricted or prohibited (McCracken et al. 2001). At present, these birds too appear to be holding their own with a population of 50.000-70.000 individuals (BirdLife International 2004).