The Remarkable Muscovy Duck

A great many ducks are remarkable. Among them is the Muscovy duck Cairina moschata. Let’s just consider for a moment how remarkable Muscovy ducks are…

Caption: my hope with respect to this image is that it takes you a few moments to work out what’s going on. It’s a male Muscovy duck, eyes closed, preening his chest with his head inverted. This was a captive bird photographed on La Palma in the Canary Islands in 2014. Image: Darren Naish.

Before I continue, some caveats: the Muscovy duck occurs as a wild species in the southern USA, Mexico, and then south to Argentina and Uruguay. However, most of us know it as a domestic species, and all my images here are of the domestic form. The name ‘Muscovy duck’ is usually said to reflect a confused connection to the Moscow region, one suggestion being that this is due to shipment of the birds by a European trading company called the Muscovite or Muscovy company. But maybe this is nonsense, and there are other suggestions that the name is a corrupted reference to an indigenous South American culture or location once associated with the bird. Another suggestion is that the bird got its English name merely to mark it as unusual and foreign. The equally wrong name Barbary duck is also used for the species, especially in cookery.

The biggest duck. The Muscovy duck is big and probably the biggest of all ducks, with large males reaching 86 cm in length and exceeding 7 kg. It’s highly dimorphic in size, females sometimes weighing half as much as males. Males are extravagant in terms of secondary sexual characteristics, combining a feather crest on the crown, a pronounced knob at the bill base, and (often red, sometimes black) carunculated, naked skin across the face. An especially curved, large claw is present on the second toe. It’s used in fighting: a Muscovy duck will hold another duck (by the neck) with its bill while beating it with its wings and raking with the claws. The Muscovy is quite pneumatic in the skeleton, with pneumatic invasions of the coracoid that are otherwise not common in ducks (O’Connor 2004).

Caption: a domestic male Muscovy duck revealing key facial features of this species. Note the naked facial skin (in this individual, there are few carunculations, maybe because he’s young), prominent knob at the base of the bill, and feather crest. Image: Darren Naish.

What sort of a duck are you, exactly? On the issue of phylogenetics and correct taxonomic placement, the Muscovy duck has proved a bit of a problem. I definitely prefer (because that’s how this works…) the hypothesis that it’s a tadornine: part of the group that includes shelducks and sheldgeese (Livezey 1997, Johnson & Sorenson 1999, Sun et al. 2017). This placement would explain a few unusual features of Muscovy duck biology, since they’re like shelducks and unlike most anatine ducks in being polygynous with a prominent degree of sexual size dimorphism, and in being cavity nesters that produce relatively large clutches (9-11 eggs) (Livezey 1996).

Caption: numerous competing views of duck phylogeny exist. In this highly simplified version (based on Sun et al. 2017), tadornines are closer to dabbling ducks than to seaducks. Muscovy ducks are part of the Tadorna lineage in the study concerned. The images used here were created for my in-prep textbook project, which is still underway and can be supported at my patreon. Image: Darren Naish.

This suggested placement has been disputed on anatomical grounds, however, where studies have tended to find Muscovy ducks to be anatines close to pygmy geese (Nettapus) and within a clade that includes diving ducks (aythyins), dabbling ducks (anatins) and others (Livezey 1997). Some molecular studies also find Muscovy ducks to be part of the aythyin + anatin lineage rather than the Tadorna one (Donne-Goussé et al. 2002). An older idea, proposed mostly on the basis of behaviour, is that Muscovy ducks are close to perching ducks (the mostly extravagant [in males] Aix ducks, Brazilian teal Amazonetta brasiliensis and so on), since they all share weak or absent pair bonds, reduced or absent precopulatory displays and have similar looking ducklings (Johnsgard 1961). There’s a long tradition of paying lots of attention to mating displays and so on in wildfowl and emphasising their significance in elucidating relatedness, but I think it’s fair to say that we need to combine these traits with other lines of evidence and not rely on them as being all that meaningful… not that anyone does these days, mind you.

Anyway… it might be that Muscovy ducks are related to both perching ducks and tadornines, since some molecular studies find Aix and Cairina to belong in a clade with Tadorna (Sun et al. 2017).

Caption: the sexually aggressive proclivities of the Muscovy aren’t in evidence all the time. This male (photographed in the Welsh Mountain Zoo in 2014) was allopreening his female companion. Image: Darren Naish.

Domestication. Another reason that the Muscovy duck is special is because it’s been domesticated, this obviously being a wholly separate, South American event from the Eurasian domestication of the Mallard Anas platyrhynchos. Artistic evidence (both images on pottery, and sculpture) demonstrates that the domestic Muscovy was present in Peru round about a thousand years ago (Gamboa 2019) and equally old evidence comes from Ecuador (Stahl et al. 2006); especially old Muscovy bones revealing signs of domestication are known from Bolivia and date to something like the 10th century (Gamboa 2019). So far as I can tell, a specific place of domestication hasn’t been identified, and all indications are that the birds were traded across South America.

Europeans took Muscovy ducks back to Europe (where they were first written about in the 1550s), and here they were bred and crossed with domestic Mallards. They’ve also been taken to African countries, and to India and China, where new local forms have been bred. Genetic studies of these African and Asian variants are underway.

Caption: Muscovy duck sexual behaviour is aggressive, with most (maybe all?) events involving rape. Male Muscovies will rape other birds, as evidenced by this photo taken on a Welsh farm in 2014. Image: Darren Naish.

Hybrids combine the traits of both species, being fast-growing like Mallards but reaching the large size typical of the Muscovy. They’re sometimes infertile (hence the name ‘mulard’, originating from ‘mule mallard’) but sometimes not. If Muscovy ducks are tadornines as discussed above, the very existence of these hybrids is remarkable since we’re talking about genetic pairing between the members of groups that have been separate for tens of millions of years (at least since the Early Miocene if certain fossils are tadornines as proposed: Worthy & Lee 2008).

I’ve never eaten Muscovy duck meat but apparently it tastes something like beef and is often much darker than that of other domestic ducks.

As ever, there is much more that could be said but my time is up. For previous Tetrapod Zoology articles on duck and other wildfowl/waterfowl, see…

Articles like this are possible because of the support I receive at patreon. Please consider supporting my research and writing if you don’t already, thank you so much. 

Refs - -

Donne-Goussé, C., Laudet, V. & Hänni, C. 2002. A molecular phylogeny of anseriforms based on mitochondrial DNA analysis. Molecular Phylogenetics and Evolution 23, 339-356.

Gamboa, J. 2019. The modern ontological natures of the Cairina moschata (Linnaeus, 1758) duck. Cases from Perú, the northern hemisphere, and digital communities. Anthropozoologica 54, 123-139.

Johnsgard, P. A. 1961. The taxonomy of the Anatidae – a behavioural analysis. Ibis 103, 71-85.

Johnson, K. P. & Sorenson, M. D. 1999. Phylogeny and biogeography of dabbling ducks (genus: Anas): a comparison of molecular and morphological evidence. The Auk 116, 792-805.

Livezey, B. C. 1996. A phylogenetic reassessment of the tadornine-anatine divergence (Aves: Anseriformes: Anatidae). Annals of Carnegie Museum 65, 27-88.

Livezey, B. C. 1997. A phylogenetic classification of waterfowl (Aves: Anseriformes), including selected fossil species. Annals of Carnegie Museum 66, 457-496.

O’Connor, P. M. 2004. Pulmonary pneumaticity in the postcranial skeleton of extant Aves: a case study examining Anseriformes. Journal of Morphology 261, 141-161.

Stahl, P. W., Muse, M. C. & Delgado-Espinoza, F. 2006. New Evidence for Precolumbian Muscovy Duck Cairina moschata from Ecuador. Ibis 148, 657-663.

Sun, Z., Pan, T., Hu, C., Sun, L., Ding, H., Wang, H., Zhang, C., Jin, H., Chang, Q., Kan, X. & Zhang, B. 2017. Rapid and recent diversification patterns in Anseriformes birds: Inferred from molecular phylogeny and diversification analyses. PLoS ONE 12 (9): e0184529.

Worthy, T. H. & Lee, M. S. Y. 2008. Affinities of Miocene waterfowl (Anatidae: Manuherikia, Dunstanetta and Miotadorna) from the St Bathans Fauna, New Zealand. Palaeontology 51, 677-708.