Perching duck

Perching duck
File:Woodduck95.jpg
Pair of Wood Ducks (Aix sponsa)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Anseriformes
Family:	Anatidae
Subfamily:	Anatinae
Tribe:	Cairinini
Species
Aix galericulata Aix sponsa Cairina moschata

The perching ducks ("Cairininae" or "Cairinini") were previously treated as a small group of ducks in the duck, goose and swan family Anatidae, grouped together on the basis of their readiness to perch high in trees. It has been subsequently shown that the grouping is paraphyletic and their apparent similarity results from convergent evolution, with the different members more closely related to various other ducks than to each other (Livezey 1986).

The species previously included, and their current subfamilial allocation, are:

Plectropterinae

• Spur-winged Goose Plectropterus gambensis

Tadorninae

• Salvadori's Teal Salvadorina waigiuensis (initially placed in Anatinae)
• Blue Duck Hymenolaimus malacorhynchos
• Torrent Duck Merganetta armata

Anatinae

• Brazilian Teal Amazonetta brasiliensis

In addition, several species cannot with certainty be allocated to a subfamily, though they do not form a distinct clade. Rather, their characters are too ambiguous to allow unequivocal placement based on the available data (Livezey 1986, Sraml et al. 1996, Johnson & Sorenson 1999):

• Comb Duck Sarkidiornis melanotos: Tadorninae or basal Anatinae?
• Pink-eared Duck Malacorhynchus membranaceus: Tadorninae or Oxyurinae?
• Hartlaub's Duck Pteronetta hartlaubi: Anatinae or a very distinct clade?
• Green Pygmy Goose Nettapus pulchellus: Anatinae or a Gondwanan clade?
• Cotton Pygmy Goose Nettapus coromandellanus: Anatinae or a Gondwanan clade?
• African Pygmy Goose Nettapus auritus: Anatinae or a Gondwanan clade?
• Muscovy Duck Cairina moschata: Anatinae or Tadorninae?
• White-winged Duck Cairina scutulata: Anatinae or closer to Aythyinae?
• Wood Duck Aix sponsa: Anatinae or Tadorninae?
• Mandarin Duck Aix galericulata: Anatinae or Tadorninae?
• Ringed Teal Callonetta leucophrys: Anatinae or Tadorninae?
• Maned Duck Chenonetta jubata: Anatinae or Tadorninae?

References

• Johnson, Kevin P. & Sorenson, Michael D. (1999): Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence. Auk 116(3): 792–805. PDF fulltext

• Livezey, Bradley C. (1986): A phylogenetic analysis of recent anseriform genera using morphological characters. Auk 103(4): 737-754. PDF fulltext

• Sraml, M.; Christidis, L.; Easteal, S.; Horn, P. & Collet, C. (1996): Molecular Relationships Within Australasian Waterfowl (Anseriformes). Australian Journal of Zoology 44(1): 47-58. doi:10.1071/ZO9960047 (HTML abstract)

This article is part of Project Bird Taxonomy, a All Birds project that aims to write comprehensive articles on every order, family and other taxonomic rank related to birds.