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American black duck

The American black duck (Anas rubripes) is a large dabbling duck in the family Anatidae. It was described by William Brewster in 1902. It is the heaviest species in the genus Anas, weighing 720–1,640 g (1.59–3.62 lb) on average and measuring 54–59 cm (21–23 in) in length with an 88–95 cm (35–37 in) wingspan. It somewhat resembles the female and eclipse male mallard in coloration, but has a darker plumage. The male and female are generally similar in appearance, but the male's bill is yellow while the female's is dull green with dark marks on the upper mandible. It is native to eastern North America. During the breeding season, it is usually found in coastal and freshwater wetlands from Saskatchewan to the Atlantic in Canada and the Great Lakes and the Adirondacks in the United States. It is a partially migratory species, mostly wintering in the east-central United States, especially in coastal areas.

American black duck
American black duck in flight
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anas
Species:
A. rubripes
Binomial name
Anas rubripes
(Brewster, 1902)
Synonyms

Anas obscura Gmelin, 1789

It interbreeds regularly and extensively with the mallard, to which it is closely related. The female lays six to fourteen oval eggs, which have smooth shells and come in varied shades of white and buff green. Hatching takes 30 days on average. Incubation usually takes 25 to 26 days, with both sexes sharing duties, although the male usually defends the territory until the female reaches the middle of her incubation period. It takes about six weeks to fledge. Once the eggs hatch, the hen leads the brood to rearing areas with abundant invertebrates and vegetation.

The American black duck is considered to be a species of least concern by the International Union for Conservation of Nature (IUCN), although some populations of the species are in decline. It has long been valued as a game bird. Habitat loss due to drainage, global warming, filling of wetlands due to urbanization and rising sea levels are major reasons for the declining population of the American black duck. The United States Fish and Wildlife Service has been purchasing and managing the habitat of this species in many areas to support the migratory stopover, wintering and breeding populations. The Atlantic Coast Joint Venture also protects habitat through restoration and land acquisition projects, mostly within their wintering and breeding areas.

Taxonomy and etymology Edit

American ornithologist William Brewster described the American black duck as Anas obscura rubripes, for "red-legged black duck",[2] in his landmark article "An undescribed form of the black duck (Anas obscura)," in The Auk in 1902, to distinguish between the two kinds of black ducks found in New England. One of them was described as being comparatively small, with brownish legs and an olivaceous or dusky bill, and the other as being comparatively larger, with a lighter skin tone, bright red legs and a clear yellow bill.[2] The larger of the two was described as Anas obscura by the German naturalist Johann Friedrich Gmelin in 1789[1] in the 13th edition of the Systema Naturae, Part 2, and he based it on the "Dusky Duck" of Welsh naturalist Thomas Pennant.[2] The current scientific name, Anas rubripes, is derived from Latin, with Anas meaning "duck" and rubripes coming from ruber, "red", and pes, "foot".[3]

Pennant, in Arctic Zoology, Volume 2, described this duck as coming "from the province of New York" and having "a long and narrow dusky bill, tinged with blue: chin white: neck pale brown, streaked downwards with dusky lines."[2] In a typical obscura, characteristics such as greenish black, olive green or dusky olive bill; olivaceous brown legs with at most one reddish tinge; the nape and pileum nearly uniformly dark; spotless chin and throat; fine linear and dusky markings on the neck and sides of the head, rather than blackish, do not vary with age or season.[2]

Description Edit

 
Male with a yellow beak and showing speculum
 
Female with a dull green beak

The American black duck weighs 720–1,640 g (1.59–3.62 lb) and measures 54–59 cm (21–23 in) in length with a 88–95 cm (35–37 in) wingspan.[4] This species has the highest mean body mass in the genus Anas, with a sample of 376 males averaging 1.4 kg (3.1 lb) and 176 females averaging 1.1 kg (2.4 lb), although its size is typically quite similar to that of the familiar mallard.[5][6] The American black duck somewhat resembles the female mallard in coloration, although the black duck's plumage is darker.[7] Males and females are generally similar in appearance, but the male's bill is yellow while the female's is dull green with dark marks on the upper mandible,[8] which is occasionally flecked with black.[9][10] The head is brown, but is slightly lighter in tone than the darker brown body. The cheeks and throat are streaked brown, with a dark streak going through the crown and dark eye.[7] The speculum feathers are iridescent violet-blue with predominantly black margins.[8] The fleshy orange feet of the duck have dark webbing.[11]

Both male and female American black ducks produce similar calls to their close relative, the mallard, with the female producing a loud sequence of quacks which falls in pitch.[12]

In flight, the white lining of the underwings can be seen in contrast to the blackish underbody and upperside.[7][13] The purple speculum lacks white bands at the front and rear, and rarely has a white trailing edge. A dark crescent is visible on the median underwing primary coverts.[13]

Juveniles resemble adult females, but have broken narrow pale edges of underpart feathers, which give a slightly streaked rather than scalloped appearance, and the overall appearance is browner rather than uniformly blackish. Juvenile males have brownish-orange feet while juvenile females have brownish feet and a dusky greyish-green bill.[13]

Distribution and habitat Edit

 
Anas rubripes female, Hudson River, New Jersey, USA

The American black duck is endemic to eastern North America.[14] In Canada, the range extends from northeastern Saskatchewan to Newfoundland and Labrador.[7] In the United States, it is found in northern Illinois, Michigan, New Jersey, Ohio, Connecticut, Vermont, South Dakota, central West Virginia, Maine and on the Atlantic coast to North Carolina.[7][15]

The American black duck is a habitat generalist as it is associated with tidal marshes and present throughout the year in salt marshes from the Gulf of Maine to coastal Virginia.[16] It usually prefers freshwater and coastal wetlands throughout northeastern America, including brackish marshes, estuaries and edges of backwater ponds and rivers lined by speckled alder.[7][15] It also inhabits beaver ponds, shallow lakes with sedges and reeds, bogs in open boreal and mixed hardwood forests, as well as forested swamps.[15] Populations in Vermont have also been found in glacial kettle ponds surrounded by bog mats.[15] During winter, the American black duck mostly inhabits brackish marshes bordering bays, agricultural marshes, flooded timber, agricultural fields, estuaries and riverine areas.[15] Ducks usually take shelter from hunting and other disturbances by moving to brackish and fresh impoundments on conservation land.[4]

Behavior Edit

Feeding Edit

The American black duck is an omnivorous species[17] with a diverse diet.[18] It feeds by dabbling in shallow water and grazing on land.[17] Its plant diet primarily includes a wide variety of wetland grasses and sedges, and the seeds, stems, leaves and root stalks of aquatic plants, such as eelgrass, pondweed and smartweed.[7][8] Its animal diet includes mollusks, snails, amphipods, insects, mussels and small fishes.[17][18]

During the breeding season, the diet of the American black duck consists of approximately 80% plant food and 20% animal food. The animal food diet increases to 85% during winter.[17] During nesting, the proportion of invertebrates increases.[8] Ducklings mostly eat water invertebrates for the first 12 days after hatching, including aquatic snowbugs, snails, mayflies, dragonflies, beetles, flies, caddisflies and larvae. After this, they shift to seeds and other plant food.[17]

Breeding Edit

 
A female American black duck (top left) and a male mallard (bottom right) in eclipse plumage

The breeding habitat includes alkaline marshes, acid bogs, lakes, ponds, rivers, marshes, brackish marshes and the margins of estuaries and other aquatic environments in northern Saskatchewan, Manitoba, across Ontario, Quebec and the Atlantic Canadian Provinces, plus the Great Lakes and the Adirondacks in the United States.[19] It is partially migratory, and many winter in the east-central United States, especially coastal areas; some remain year-round in the Great Lakes region.[20] This duck is a rare vagrant to Great Britain and Ireland, where over the years several birds have settled in and bred with the local mallard.[21] The resulting hybrid can present considerable identification difficulties.[21]

Nest sites are well-concealed on the ground, often in uplands. Egg clutches have six to fourteen oval eggs,[11] which have smooth shells and come in varied shades of white and buff green.[19] On average, they measure 59.4 mm (2.34 in) long, 43.2 mm (1.70 in) wide and weigh 56.6 g (0.125 lb).[19] Hatching takes 30 days on average.[11] The incubation period varies,[19] but usually takes 25 to 26 days.[22] Both sexes share duties, although the male usually defends the territory until the female reaches the middle of her incubation period.[22] It takes about six weeks to fledge.[22] Once the eggs hatch, the hen leads the brood to rearing areas with abundant invertebrates and vegetation.[22]

The American black duck interbreeds regularly and extensively with the mallard, to which it is closely related.[23] Some authorities even consider the black duck to be a subspecies of the mallard instead of a separate species. Mank et al. argue that this is in error as the extent of hybridization alone is not a valid means to delimitate Anas species.[24]

 
Chart showing differences between the American black duck and the female mallard

It has been proposed that the American black duck and the mallard were formerly separated by habitat preference, with the American black duck's dark plumage giving it a selective advantage in shaded forest pools in eastern North America, and the mallard's lighter plumage giving it an advantage in the brighter, more open prairie and plains lakes.[25] According to this view, recent deforestation in the east and tree planting on the plains has broken down this habitat separation, leading to the high levels of hybridization now observed.[26] However, rates of past hybridization are unknown in this and most other avian hybrid zones, and it is merely presumed in the case of the American black duck that past hybridization rates were lower than those seen today. Also, many avian hybrid zones are known to be stable and longstanding despite the occurrence of extensive interbreeding.[23] The American black duck and the local mallard are now very hard to distinguish by means of microsatellite comparisons, even if many specimens are sampled.[27] Contrary to this study's claims, the question of whether the American haplotype is an original mallard lineage is far from resolved. Their statement, "Northern black ducks are now no more distinct from mallards than their southern conspecifics" only holds true in regard to the molecular markers tested.[24] As birds indistinguishable according to the set of microsatellite markers still can look different, there are other genetic differences that were simply not tested in the study.[24]

In captivity studies, it has been discovered that the hybrids follow Haldane's Rule, with hybrid females often dying before they reach sexual maturity, thereby supporting the case for the American black duck being a distinct species.[23][28]

Nest predators and hazards Edit

The apex nest predators of the American black duck include American crows, gulls and raccoons, especially in tree nests.[17] Hawks and owls are also major predators of adults. Bullfrogs and snapping turtles eat many ducklings.[17] Ducklings often catch diseases caused by protozoan blood parasites transmitted by bites of insects such as blackflies.[17] They are also vulnerable to lead shot poisoning, known as plumbism, due to their bottom-foraging food habits.[17]

Status and conservation Edit

Since 1988, the American black duck has been rated as least concern on the IUCN Red List of Endangered Species.[1] This is because the range of this species is extremely large, which is not near the threshold of vulnerable species.[1] In addition, the total population is large, and, although it is declining, it is not declining fast enough to make the species vulnerable.[1] It has long been valued as a game bird, being extremely wary and fast flying.[29] Habitat loss due to drainage, filling of wetlands due to urbanization, global warming and rising sea levels are major reasons for the declining population.[14] Some conservationists consider hybridization and competition with the mallard as an additional source of concern should this decline continue.[30][31] Hybridization itself is not a major problem; natural selection makes sure that the best-adapted individuals have the most offspring.[32] However, the reduced viability of female hybrids causes some broods to fail in the long run due to the death of the offspring before reproducing themselves.[33] While this is not a problem in the plentiful mallard, it might place an additional strain on the American black duck's population. Recent research conducted for the Delta Waterfowl Foundation suggests that hybrids are a result of forced copulations and not a normal pairing choice by black hens.[34]

The United States Fish and Wildlife Service has continued to purchase and manage habitat in many areas to support the migratory stopover, wintering and breeding populations of the American black duck.[14] In addition, the Montezuma National Wildlife Refuge has purchased and restored over 1,000 acres of wetlands to provide stopover habitat for over 10,000 American black ducks during fall migration.[14] Also, the Atlantic Coast Joint Venture has been protecting the habitat of the American black duck through habitat restoration and land acquisition projects, mostly within their wintering and breeding areas.[14] In 2003, a Boreal Forest Conservation Framework was adopted by conservation organizations, industries and First Nations to protect the Canadian boreal forests, including the American black duck's eastern Canadian breeding range.[14]

References Edit

  1. ^ a b c d e BirdLife International (2021). "Anas rubripes". IUCN Red List of Threatened Species. 2021: e.T22680174A137023072. doi:10.2305/IUCN.UK.2021-3.RLTS.T22680174A137023072.en. Retrieved 13 July 2022.
  2. ^ a b c d e Brewster, William (1902). "An undescribed form of the black duck (Anas obscura)". The Auk. American Ornithologists Union. 19 (2): 183–188. doi:10.2307/4069311. ISSN 0004-8038. JSTOR 4069311 – via Biodiversity Heritage Library.
  3. ^ Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. Christopher Helm. pp. 46, 340. ISBN 978-1-4081-2501-4.
  4. ^ a b . www.allaboutbirds.org. 2011. Archived from the original on 2017-02-17. Retrieved 2017-06-29.
  5. ^ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
  6. ^ CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), ISBN 978-1-4200-6444-5.
  7. ^ a b c d e f g Smith, Christopher (2000). Field Guide to Upland Birds and Waterfowl. Wilderness Adventures Press. p. 60. ISBN 9781885106209.
  8. ^ a b c d Kear, Janet (2005). Ducks, Geese and Swans: Species accounts (Cairina to Mergus). Oxford University Press. p. 509. ISBN 9780198610090.
  9. ^ Potter, Eloise F.; Parnell, James F.; Teulings, Robert P.; Davis, Ricky (2015). Birds of the Carolinas. The University of North Carolina Press. p. 47. ISBN 9781469625652.
  10. ^ Dunn, Jon Lloyd; Alderfer, Jonathan K. (2006). National Geographic Field Guide to the Birds of North America. National Geographic Books. p. 30. ISBN 9780792253143.
  11. ^ a b c Ryan, James M. (2009). Adirondack Wildlife: A Field Guide. University Press of New England. p. 118. ISBN 9781584657491.
  12. ^ "American Black Duck". The Cornell Lab - All About Birds. Retrieved 20 December 2019.
  13. ^ a b c Beaman, Mark; Madge, Steve (2010). The Handbook of Bird Identification: For Europe and the Western Palearctic. A&C Black. p. 163. ISBN 9781408135235.
  14. ^ a b c d e f Wells, Jeffrey V. (2010). Birder's Conservation Handbook: 100 North American Birds at Risk. Princeton University Press. pp. 56–57. ISBN 978-1400831517.
  15. ^ a b c d e U.S. Department of the Interior, National Park Service (2007). Cape Cod National Seashore (N.S.), Hunting Program: Environmental Impact Statement. pp. 83–84.
  16. ^ Roman, Charles T. (2012). Tidal Marsh Restoration: A Synthesis of Science and Management. Island Press. p. 132. ISBN 9781610912297.
  17. ^ a b c d e f g h i Eastman, John Andrew (1999). Birds of Lake, Pond, and Marsh: Water and Wetland Birds of Eastern North America. Stackpole Books. pp. 57–58. ISBN 9780811726818.
  18. ^ a b Maehr, David S.; Kale II, Herbert W. (2005). Florida's Birds: A Field Guide and Reference. Pineapple Press Inc. p. 56. ISBN 9781561643356.
  19. ^ a b c d Baldassarre, Guy A. (2014). Ducks, Geese, and Swans of North America. Johns Hopkins University Press. pp. 353–356. ISBN 9781421407517.
  20. ^ Jerry R., Longcore; McAuley, Daniel G.; Hepp, Gary R.; Rhymer, Judith M. (2020). . In Poole, Alan F; Gill, Frank B (eds.). American Black Duck: Anas rubripes. doi:10.2173/bow.ambduc.01. Archived from the original on 2016-03-25. Retrieved 2017-06-30.
  21. ^ a b Evans, Lee G. R. (1994). Rare Birds in Britain 1800-1990. LGRE Productions Incorporated. pp. 13–14. ISBN 9781898918004.
  22. ^ a b c d Schwartz, Nancy A. (2010). Wildlife Rehabilitation: Basic Life Support. Xlibris Corporation. ISBN 9781453531921.
  23. ^ a b c McCarthy, Eugene M. (2006). Handbook of Avian Hybrids of the World. Oxford University Press.
  24. ^ a b c Mank, Judith E.; Carlson, John E.; Brittingham, Margaret C. (2004). "A century of hybridization: Decreasing genetic distance between American black ducks and mallards". Conservation Genetics. 5 (3): 395–403. doi:10.1023/B:COGE.0000031139.55389.b1. S2CID 24144598.
  25. ^ Armistead, George L.; Sullivan, Brian L. (2015). Better Birding: Tips, Tools, and Concepts for the Field. Princeton University Press. p. 13. ISBN 9780691129662.
  26. ^ Johnsgard, Paul A. (1967). "Sympatry Changes and Hybridization Incidence in Mallards and Black Ducks". American Midland Naturalist. 77 (1): 51–63. doi:10.2307/2423425. JSTOR 2423425.
  27. ^ Avise, John C.; Ankney, C. Davison; Nelson, William S. (1990). "Mitochondrial Gene Trees and the Evolutionary Relationship of Mallard and Black Ducks". Evolution. 44 (4): 1109–1119. doi:10.2307/2409570. JSTOR 2409570. PMID 28569026.
  28. ^ Kirby, Ronald E.; Sargeant, Glen A.; Shutler, Dave (2004). "Haldane's rule and American black duck × mallard hybridization". Canadian Journal of Zoology. 82 (11): 1827–1831. doi:10.1139/z04-169.
  29. ^ Anonymous (2007). Lake Umbagog National Wildlife Refuge (N.W.R.), Conservation Plan: Environmental Impact Statement. pp. 142–143.
  30. ^ Rhymer, Judith M. (2006). . Acta Zoologica Sinica. 52 (Supplement): 583–585. Archived from the original (PDF) on 2013-12-03.
  31. ^ Rhymer, Judith M.; Simberloff, Daniel (1996). "Extinction by hybridization and introgression". Annu. Rev. Ecol. Syst. 27: 83–109. doi:10.1146/annurev.ecolsys.27.1.83.
  32. ^ Ashton, Mike (2014). Domestic Duck. Crowood Press. p. 7. ISBN 9781847979704.
  33. ^ Newton, Ian (2003). Speciation and Biogeography of Birds. Academic Press. p. 417. ISBN 9780080924991.
  34. ^ Wintersteen, Kyle (2013-03-01). . American Hunter. Archived from the original on 2016-03-26. Retrieved 2013-03-02.

External links Edit

  • American Black Duck Species Account – Cornell Lab of Ornithology
  • "American Black Duck media". Internet Bird Collection.
  • American Black Duck photo gallery at VIREO (Drexel University)
  • Interactive range map of Anas rubripes at IUCN Red List maps

american, black, duck, anas, rubripes, large, dabbling, duck, family, anatidae, described, william, brewster, 1902, heaviest, species, genus, anas, weighing, average, measuring, length, with, wingspan, somewhat, resembles, female, eclipse, male, mallard, color. The American black duck Anas rubripes is a large dabbling duck in the family Anatidae It was described by William Brewster in 1902 It is the heaviest species in the genus Anas weighing 720 1 640 g 1 59 3 62 lb on average and measuring 54 59 cm 21 23 in in length with an 88 95 cm 35 37 in wingspan It somewhat resembles the female and eclipse male mallard in coloration but has a darker plumage The male and female are generally similar in appearance but the male s bill is yellow while the female s is dull green with dark marks on the upper mandible It is native to eastern North America During the breeding season it is usually found in coastal and freshwater wetlands from Saskatchewan to the Atlantic in Canada and the Great Lakes and the Adirondacks in the United States It is a partially migratory species mostly wintering in the east central United States especially in coastal areas American black duckAmerican black duck in flightConservation statusLeast Concern IUCN 3 1 1 Scientific classificationDomain EukaryotaKingdom AnimaliaPhylum ChordataClade DinosauriaClass AvesOrder AnseriformesFamily AnatidaeGenus AnasSpecies A rubripesBinomial nameAnas rubripes Brewster 1902 SynonymsAnas obscura Gmelin 1789It interbreeds regularly and extensively with the mallard to which it is closely related The female lays six to fourteen oval eggs which have smooth shells and come in varied shades of white and buff green Hatching takes 30 days on average Incubation usually takes 25 to 26 days with both sexes sharing duties although the male usually defends the territory until the female reaches the middle of her incubation period It takes about six weeks to fledge Once the eggs hatch the hen leads the brood to rearing areas with abundant invertebrates and vegetation The American black duck is considered to be a species of least concern by the International Union for Conservation of Nature IUCN although some populations of the species are in decline It has long been valued as a game bird Habitat loss due to drainage global warming filling of wetlands due to urbanization and rising sea levels are major reasons for the declining population of the American black duck The United States Fish and Wildlife Service has been purchasing and managing the habitat of this species in many areas to support the migratory stopover wintering and breeding populations The Atlantic Coast Joint Venture also protects habitat through restoration and land acquisition projects mostly within their wintering and breeding areas Contents 1 Taxonomy and etymology 2 Description 3 Distribution and habitat 4 Behavior 4 1 Feeding 4 2 Breeding 4 3 Nest predators and hazards 5 Status and conservation 6 References 7 External linksTaxonomy and etymology EditAmerican ornithologist William Brewster described the American black duck as Anas obscura rubripes for red legged black duck 2 in his landmark article An undescribed form of the black duck Anas obscura in The Auk in 1902 to distinguish between the two kinds of black ducks found in New England One of them was described as being comparatively small with brownish legs and an olivaceous or dusky bill and the other as being comparatively larger with a lighter skin tone bright red legs and a clear yellow bill 2 The larger of the two was described as Anas obscura by the German naturalist Johann Friedrich Gmelin in 1789 1 in the 13th edition of the Systema Naturae Part 2 and he based it on the Dusky Duck of Welsh naturalist Thomas Pennant 2 The current scientific name Anas rubripes is derived from Latin with Anas meaning duck and rubripes coming from ruber red and pes foot 3 Pennant in Arctic Zoology Volume 2 described this duck as coming from the province of New York and having a long and narrow dusky bill tinged with blue chin white neck pale brown streaked downwards with dusky lines 2 In a typical obscura characteristics such as greenish black olive green or dusky olive bill olivaceous brown legs with at most one reddish tinge the nape and pileum nearly uniformly dark spotless chin and throat fine linear and dusky markings on the neck and sides of the head rather than blackish do not vary with age or season 2 Description Edit nbsp Male with a yellow beak and showing speculum nbsp Female with a dull green beakThe American black duck weighs 720 1 640 g 1 59 3 62 lb and measures 54 59 cm 21 23 in in length with a 88 95 cm 35 37 in wingspan 4 This species has the highest mean body mass in the genus Anas with a sample of 376 males averaging 1 4 kg 3 1 lb and 176 females averaging 1 1 kg 2 4 lb although its size is typically quite similar to that of the familiar mallard 5 6 The American black duck somewhat resembles the female mallard in coloration although the black duck s plumage is darker 7 Males and females are generally similar in appearance but the male s bill is yellow while the female s is dull green with dark marks on the upper mandible 8 which is occasionally flecked with black 9 10 The head is brown but is slightly lighter in tone than the darker brown body The cheeks and throat are streaked brown with a dark streak going through the crown and dark eye 7 The speculum feathers are iridescent violet blue with predominantly black margins 8 The fleshy orange feet of the duck have dark webbing 11 Both male and female American black ducks produce similar calls to their close relative the mallard with the female producing a loud sequence of quacks which falls in pitch 12 In flight the white lining of the underwings can be seen in contrast to the blackish underbody and upperside 7 13 The purple speculum lacks white bands at the front and rear and rarely has a white trailing edge A dark crescent is visible on the median underwing primary coverts 13 Juveniles resemble adult females but have broken narrow pale edges of underpart feathers which give a slightly streaked rather than scalloped appearance and the overall appearance is browner rather than uniformly blackish Juvenile males have brownish orange feet while juvenile females have brownish feet and a dusky greyish green bill 13 Distribution and habitat Edit nbsp Anas rubripes female Hudson River New Jersey USAThe American black duck is endemic to eastern North America 14 In Canada the range extends from northeastern Saskatchewan to Newfoundland and Labrador 7 In the United States it is found in northern Illinois Michigan New Jersey Ohio Connecticut Vermont South Dakota central West Virginia Maine and on the Atlantic coast to North Carolina 7 15 The American black duck is a habitat generalist as it is associated with tidal marshes and present throughout the year in salt marshes from the Gulf of Maine to coastal Virginia 16 It usually prefers freshwater and coastal wetlands throughout northeastern America including brackish marshes estuaries and edges of backwater ponds and rivers lined by speckled alder 7 15 It also inhabits beaver ponds shallow lakes with sedges and reeds bogs in open boreal and mixed hardwood forests as well as forested swamps 15 Populations in Vermont have also been found in glacial kettle ponds surrounded by bog mats 15 During winter the American black duck mostly inhabits brackish marshes bordering bays agricultural marshes flooded timber agricultural fields estuaries and riverine areas 15 Ducks usually take shelter from hunting and other disturbances by moving to brackish and fresh impoundments on conservation land 4 Behavior EditFeeding Edit The American black duck is an omnivorous species 17 with a diverse diet 18 It feeds by dabbling in shallow water and grazing on land 17 Its plant diet primarily includes a wide variety of wetland grasses and sedges and the seeds stems leaves and root stalks of aquatic plants such as eelgrass pondweed and smartweed 7 8 Its animal diet includes mollusks snails amphipods insects mussels and small fishes 17 18 During the breeding season the diet of the American black duck consists of approximately 80 plant food and 20 animal food The animal food diet increases to 85 during winter 17 During nesting the proportion of invertebrates increases 8 Ducklings mostly eat water invertebrates for the first 12 days after hatching including aquatic snowbugs snails mayflies dragonflies beetles flies caddisflies and larvae After this they shift to seeds and other plant food 17 Breeding Edit nbsp A female American black duck top left and a male mallard bottom right in eclipse plumageThe breeding habitat includes alkaline marshes acid bogs lakes ponds rivers marshes brackish marshes and the margins of estuaries and other aquatic environments in northern Saskatchewan Manitoba across Ontario Quebec and the Atlantic Canadian Provinces plus the Great Lakes and the Adirondacks in the United States 19 It is partially migratory and many winter in the east central United States especially coastal areas some remain year round in the Great Lakes region 20 This duck is a rare vagrant to Great Britain and Ireland where over the years several birds have settled in and bred with the local mallard 21 The resulting hybrid can present considerable identification difficulties 21 Nest sites are well concealed on the ground often in uplands Egg clutches have six to fourteen oval eggs 11 which have smooth shells and come in varied shades of white and buff green 19 On average they measure 59 4 mm 2 34 in long 43 2 mm 1 70 in wide and weigh 56 6 g 0 125 lb 19 Hatching takes 30 days on average 11 The incubation period varies 19 but usually takes 25 to 26 days 22 Both sexes share duties although the male usually defends the territory until the female reaches the middle of her incubation period 22 It takes about six weeks to fledge 22 Once the eggs hatch the hen leads the brood to rearing areas with abundant invertebrates and vegetation 22 The American black duck interbreeds regularly and extensively with the mallard to which it is closely related 23 Some authorities even consider the black duck to be a subspecies of the mallard instead of a separate species Mank et al argue that this is in error as the extent of hybridization alone is not a valid means to delimitate Anas species 24 nbsp Chart showing differences between the American black duck and the female mallardIt has been proposed that the American black duck and the mallard were formerly separated by habitat preference with the American black duck s dark plumage giving it a selective advantage in shaded forest pools in eastern North America and the mallard s lighter plumage giving it an advantage in the brighter more open prairie and plains lakes 25 According to this view recent deforestation in the east and tree planting on the plains has broken down this habitat separation leading to the high levels of hybridization now observed 26 However rates of past hybridization are unknown in this and most other avian hybrid zones and it is merely presumed in the case of the American black duck that past hybridization rates were lower than those seen today Also many avian hybrid zones are known to be stable and longstanding despite the occurrence of extensive interbreeding 23 The American black duck and the local mallard are now very hard to distinguish by means of microsatellite comparisons even if many specimens are sampled 27 Contrary to this study s claims the question of whether the American haplotype is an original mallard lineage is far from resolved Their statement Northern black ducks are now no more distinct from mallards than their southern conspecifics only holds true in regard to the molecular markers tested 24 As birds indistinguishable according to the set of microsatellite markers still can look different there are other genetic differences that were simply not tested in the study 24 In captivity studies it has been discovered that the hybrids follow Haldane s Rule with hybrid females often dying before they reach sexual maturity thereby supporting the case for the American black duck being a distinct species 23 28 Nest predators and hazards Edit The apex nest predators of the American black duck include American crows gulls and raccoons especially in tree nests 17 Hawks and owls are also major predators of adults Bullfrogs and snapping turtles eat many ducklings 17 Ducklings often catch diseases caused by protozoan blood parasites transmitted by bites of insects such as blackflies 17 They are also vulnerable to lead shot poisoning known as plumbism due to their bottom foraging food habits 17 Status and conservation EditSee also Black Duck Joint Venture Since 1988 the American black duck has been rated as least concern on the IUCN Red List of Endangered Species 1 This is because the range of this species is extremely large which is not near the threshold of vulnerable species 1 In addition the total population is large and although it is declining it is not declining fast enough to make the species vulnerable 1 It has long been valued as a game bird being extremely wary and fast flying 29 Habitat loss due to drainage filling of wetlands due to urbanization global warming and rising sea levels are major reasons for the declining population 14 Some conservationists consider hybridization and competition with the mallard as an additional source of concern should this decline continue 30 31 Hybridization itself is not a major problem natural selection makes sure that the best adapted individuals have the most offspring 32 However the reduced viability of female hybrids causes some broods to fail in the long run due to the death of the offspring before reproducing themselves 33 While this is not a problem in the plentiful mallard it might place an additional strain on the American black duck s population Recent research conducted for the Delta Waterfowl Foundation suggests that hybrids are a result of forced copulations and not a normal pairing choice by black hens 34 The United States Fish and Wildlife Service has continued to purchase and manage habitat in many areas to support the migratory stopover wintering and breeding populations of the American black duck 14 In addition the Montezuma National Wildlife Refuge has purchased and restored over 1 000 acres of wetlands to provide stopover habitat for over 10 000 American black ducks during fall migration 14 Also the Atlantic Coast Joint Venture has been protecting the habitat of the American black duck through habitat restoration and land acquisition projects mostly within their wintering and breeding areas 14 In 2003 a Boreal Forest Conservation Framework was adopted by conservation organizations industries and First Nations to protect the Canadian boreal forests including the American black duck s eastern Canadian breeding range 14 References Edit a b c d e BirdLife International 2021 Anas rubripes IUCN Red List of Threatened Species 2021 e T22680174A137023072 doi 10 2305 IUCN UK 2021 3 RLTS T22680174A137023072 en Retrieved 13 July 2022 a b c d e Brewster William 1902 An undescribed form of the black duck Anas obscura The Auk American Ornithologists Union 19 2 183 188 doi 10 2307 4069311 ISSN 0004 8038 JSTOR 4069311 via Biodiversity Heritage Library Jobling James A 2010 The Helm Dictionary of Scientific Bird Names Christopher Helm pp 46 340 ISBN 978 1 4081 2501 4 a b American Black Duck www allaboutbirds org 2011 Archived from the original on 2017 02 17 Retrieved 2017 06 29 CRC Handbook of Avian Body Masses by John B Dunning Jr Editor CRC Press 1992 ISBN 978 0 8493 4258 5 CRC Handbook of Avian Body Masses 2nd Edition by John B Dunning Jr Editor CRC Press 2008 ISBN 978 1 4200 6444 5 a b c d e f g Smith Christopher 2000 Field Guide to Upland Birds and Waterfowl Wilderness Adventures Press p 60 ISBN 9781885106209 a b c d Kear Janet 2005 Ducks Geese and Swans Species accounts Cairina to Mergus Oxford University Press p 509 ISBN 9780198610090 Potter Eloise F Parnell James F Teulings Robert P Davis Ricky 2015 Birds of the Carolinas The University of North Carolina Press p 47 ISBN 9781469625652 Dunn Jon Lloyd Alderfer Jonathan K 2006 National Geographic Field Guide to the Birds of North America National Geographic Books p 30 ISBN 9780792253143 a b c Ryan James M 2009 Adirondack Wildlife A Field Guide University Press of New England p 118 ISBN 9781584657491 American Black Duck The Cornell Lab All About Birds Retrieved 20 December 2019 a b c Beaman Mark Madge Steve 2010 The Handbook of Bird Identification For Europe and the Western Palearctic A amp C Black p 163 ISBN 9781408135235 a b c d e f Wells Jeffrey V 2010 Birder s Conservation Handbook 100 North American Birds at Risk Princeton University Press pp 56 57 ISBN 978 1400831517 a b c d e U S Department of the Interior National Park Service 2007 Cape Cod National Seashore N S Hunting Program Environmental Impact Statement pp 83 84 Roman Charles T 2012 Tidal Marsh Restoration A Synthesis of Science and Management Island Press p 132 ISBN 9781610912297 a b c d e f g h i Eastman John Andrew 1999 Birds of Lake Pond and Marsh Water and Wetland Birds of Eastern North America Stackpole Books pp 57 58 ISBN 9780811726818 a b Maehr David S Kale II Herbert W 2005 Florida s Birds A Field Guide and Reference Pineapple Press Inc p 56 ISBN 9781561643356 a b c d Baldassarre Guy A 2014 Ducks Geese and Swans of North America Johns Hopkins University Press pp 353 356 ISBN 9781421407517 Jerry R Longcore McAuley Daniel G Hepp Gary R Rhymer Judith M 2020 American Black Duck Anas rubripes In Poole Alan F Gill Frank B eds American Black Duck Anas rubripes doi 10 2173 bow ambduc 01 Archived from the original on 2016 03 25 Retrieved 2017 06 30 a b Evans Lee G R 1994 Rare Birds in Britain 1800 1990 LGRE Productions Incorporated pp 13 14 ISBN 9781898918004 a b c d Schwartz Nancy A 2010 Wildlife Rehabilitation Basic Life Support Xlibris Corporation ISBN 9781453531921 a b c McCarthy Eugene M 2006 Handbook of Avian Hybrids of the World Oxford University Press a b c Mank Judith E Carlson John E Brittingham Margaret C 2004 A century of hybridization Decreasing genetic distance between American black ducks and mallards Conservation Genetics 5 3 395 403 doi 10 1023 B COGE 0000031139 55389 b1 S2CID 24144598 Armistead George L Sullivan Brian L 2015 Better Birding Tips Tools and Concepts for the Field Princeton University Press p 13 ISBN 9780691129662 Johnsgard Paul A 1967 Sympatry Changes and Hybridization Incidence in Mallards and Black Ducks American Midland Naturalist 77 1 51 63 doi 10 2307 2423425 JSTOR 2423425 Avise John C Ankney C Davison Nelson William S 1990 Mitochondrial Gene Trees and the Evolutionary Relationship of Mallard and Black Ducks Evolution 44 4 1109 1119 doi 10 2307 2409570 JSTOR 2409570 PMID 28569026 Kirby Ronald E Sargeant Glen A Shutler Dave 2004 Haldane s rule and American black duck mallard hybridization Canadian Journal of Zoology 82 11 1827 1831 doi 10 1139 z04 169 Anonymous 2007 Lake Umbagog National Wildlife Refuge N W R Conservation Plan Environmental Impact Statement pp 142 143 Rhymer Judith M 2006 Extinction by hybridization and introgression in anatine ducks Acta Zoologica Sinica 52 Supplement 583 585 Archived from the original PDF on 2013 12 03 Rhymer Judith M Simberloff Daniel 1996 Extinction by hybridization and introgression Annu Rev Ecol Syst 27 83 109 doi 10 1146 annurev ecolsys 27 1 83 Ashton Mike 2014 Domestic Duck Crowood Press p 7 ISBN 9781847979704 Newton Ian 2003 Speciation and Biogeography of Birds Academic Press p 417 ISBN 9780080924991 Wintersteen Kyle 2013 03 01 Black Ducks in Peril American Hunter Archived from the original on 2016 03 26 Retrieved 2013 03 02 External links Edit nbsp Wikimedia Commons has media related to American Black Duck nbsp Wikispecies has information related to Anas rubripes American Black Duck Species Account Cornell Lab of Ornithology American Black Duck media Internet Bird Collection American Black Duck photo gallery at VIREO Drexel University Interactive range map of Anas rubripes at IUCN Red List maps Retrieved from https en wikipedia org w index php title American black duck amp oldid 1137921794, wikipedia, wiki, book, books, library,

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