Chloephaga picta, Photo: Fabien Dany - www.fabiendany.com (Information about this image)
Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Euavialae
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Pangalloanserae
Cladus: Galloanseres
Ordo: Anseriformes
Familia: Anatidae
Subfamilia: Tadorninae
Genus: Chloephaga
Species: Chloephaga picta
Name
Chloephaga picta (Gmelin, 1789)
Original combination: Anas picta
References
Gmelin, J.F. 1789. Caroli a Linné systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I, Pars II. Editio decima tertia, aucta, reformata. - pp. 501–1032. Lipsiae. (Beer). DOI: 10.5962/bhl.title.545 Original description p.504 n.55 BHL Reference page.
Vernacular names
čeština: Husice magellanská
English: Upland goose
español: Cauquén común
français: Ouette de Magellan
日本語: マゼランガン
português do Brasil: Ganso-de-magalhães
The upland goose or Magellan goose (Chloephaga picta) is a sheldgoose of the shelduck-sheldgoose subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans.[2][3] Sheldgeese resemble true geese and display similar habits, yet they are more closely related to shelducks and ducks.[3] The two recognized subspecies of upland goose are the continental picta subspecies and the insular (island) leucoptera subspecies.
This species nests and breeds close to water (rivers, ponds, oceans) either on the ground or near it among vegetation, usually in grasslands or coastal meadows in the Falkland Islands or in southern Patagonia and Tierra del Fuego at the beginning of the austral summer. Population estimates suggest the insular subpopulations are stable, but continental populations show a recent decline in abundance.[3] Upland geese are herbivores, specializing in plant leaves, stems and seeds.[2][4]
Taxonomy
Evolution
There are strong morphological and genetic similarities between the bird fauna of the Falkland Islands and southern South America,[3] and most native bird species are usually present in both insular and continental populations. The biogeography of the region suggests that these similarities exist because in the geological past, birds from the continent might have reached the Falkland Islands either across a former land connection, during periods of lowered sea levels, or through long-distance dispersal.[5] Genetic analyses place the Magellan goose as a sister taxa to the Kelp goose, with these two species forming a monophyletic clade with the Ruddy-headed goose.[3]
Subspecies
There are two subspecies of upland goose.[2][3] The smaller mainland form, picta, also known as the lesser Magellan goose, is found from central Chile and south-central Argentina south to Tierra del Fuego. The larger insular form, leucoptera or greater Magellan goose, is indigenous to the Falkland Islands, located to the east of the southern part of South America.[2][3]
Description
Female Upland goose caring for her offspring, El Calafate, Argentina
Chloephaga picta - MHNT
Upland geese males are similar to other sheldgeese, notably the Kelp Goose (C. hybrida) due to their predominantly white plumage, while females resemble the Ruddy-headed Goose (C. rubidiceps) due to their similarly barred breast plumage. This species is 60–72.5 centimetres (23.6–28.5 in) long.[2]
Greater Magellan geese (leucoptera subspecies) are the largest birds of the Chloephaga genus. Males typically weigh 3.5–4.5 kg (7.7–9.9 lbs) and females range from 2.9 to 3.5 kg (6.4–7.7 lbs).[2] Lesser Magellan geese (picta subspecies) males weigh 2.7–3.6 kg (6.0–7.9 lbs) on average and females 2.9–3.5 kg (6.4–6.8 lbs).[2]
Upland geese display strong sexual dimorphism in their plumage. Males have white heads and breast plumage with black legs, whereas females have reddish-brown heads and breast plumage with yellow-orange legs.[6] However, two interbreeding morphs exist for males. One morph causes black-barred breast plumage while the other causes white breast plumage. A greenish-bronze speculum is also located on the inner secondary flight feathers of the adult male.[7]
Upland geese molt both their primary and secondary feathers in ponds or sheltered sea inlets, usually between late November and early January. Molting frequency depends on breeding success to some degree, since most adults that molt have either not yet mated or failed to breed.[8] Some greater Magellan geese skip this molt, retaining their ability to fly during the austral summer. While unusual, skipping this important process might have energetic advantages, since molting season can be very nutritionally taxing.[9]
In Chapter VI of On the Origin of Species, author Charles Darwin noted that the upland goose has webbing between its toes that appeared to be "rudimentary in function, though not in structure", and concluded that this was a vestigial anatomical feature in this bird.[10]
Habitat and distribution
Habitat
Upland geese usually live in small, scattered groups on most pasture types (temperate grasslands, arid lowland scrubs), favouring areas with short green grasses. However, recent land use changes towards crop fields and managed pastures have forced them to adapt to and colonize such modern landscapes.[2][11]
Distribution
Upland geese occupy the southern South American Continent (southern and central Chile and Argentina) and the Falkland Islands, with a continental distribution ranging from central Chile/southern Argentina to Tierra del Fuego, near Antarctica. Lesser Magellan geese usually reside in Patagonia or southern Chile and migrate north during the winter towards central Argentina, to their wintering grounds.[2][3] Southernmost populations are more likely to migrate,[12] with migrants reaching flight speeds of over 40 km/h.[11] In 2013, researchers identified a lesser Magellan goose in southern Brazil, redefining the northern edge of their wintering grounds.[12] Greater Magellan geese, however, do not migrate and rarely leave the Falkland Islands.[2][3] In general, population densities are highest around ponds and in green grasslands. Computer modelling of population ranges suggests that their distribution is favoured by the ample presence of green grasses to feed and breed in, and hindered by human presence, notably urbanization and oil extraction.[13]
Upland Geese in Santa Cruz Province, Argentina
There is also a sizeable introduced population on the sub-Antarctic South Georgia Island.[2][14]
Behaviour and ecology
Breeding
Upland goose breed in southern Patagonia or their native islands during the austral summer. They are monogamous, although divorce can occur, and generally return to breed in the same territory every year.[2][8] After approximately two years from birth, females can start to lay eggs, and usually do so near their birthplace. Males begin breeding later and tend to settle farther away from where they were born.[8] This sexual difference in dispersal distances causes the sex ratio of young to become biased towards the dispersing sex due to the inherent resource constraints of crowding. Therefore, upland geese tend to display a male-biased sex ratio.[15] They breed non-colonially in densely-vegetated areas, generally in September and October on the mainland, and in November on the Falkland Islands.[8] A large population of this species breeds in the New Island Nature Reserve,[16] which was created in collaboration with Falkland Conservation.
Males attract females through a courtship display in which they whistle loudly, to which the female responds with softer cackles. As they are monogamous and territorial, a violent fight may break out if a male encroaches on another's territory. Males have been found injured or dead after these fights.[17]
The simple nest is either on the ground or within 1.5 m of it, usually concealed by dense vegetation, and often located near water.[2] A clutch consists of 5-8 eggs which are incubated for about 1 month.[2][8] When the chicks hatch, they are covered in greyish-brown down. They don't remain in the nest for more than a day, quickly going to a nearby water source or feeding area, and are able to feed themselves from birth. They fledge in 9–10 weeks and reach maturity in 3 years.[2][8][17]
Vocalizations
Males make a whistling "wheep" sound, while females make a low, rattling "a-rrr" sound.[2]
Food and feeding
The upland goose is primarily a herbivore, feeding mostly of seeds, leaves, stems, and other plant matter. They are very gregarious, and flocks of thousands of birds can be found grazing in one pasture alone. They are considered pests by farmers due to the fact that they eat on the pastures that are used for cattle and sheep, and because they claim that upland geese significantly decrease crop yield.[4] However, a recent study claims that while sheldgeese do reduce wheat cover, they do not reduce overall wheat yield and they might even provide an ecosystem service through weed grazing.[18]
Threats and conservation
In the early 20th century, the Argentinian government declared the three Patagonian sheldgeese species (Ruddy-headed goose, Ashy-headed goose, and Upland goose) as pests due to claims of excessive grazing and negative effects on crop yields.[11] Since then, wildlife agencies have encouraged hunting of upland geese across the entirety of their range and without restrictions on the number of birds killed. Consequently, population surveys started suggesting continental populations were declining.[3] In 2008, all three species were classified as endangered by the Argentine government and hunting was banned, although some poaching still occurs, mostly on the mainland.[11] Recently, fox predation has drastically reduced population numbers on the mainland,[16] so national governments have established several protected areas throughout Patagonia in an attempt to conserve the species.[19]
References
BirdLife International (2016). "Chloephaga picta". IUCN Red List of Threatened Species. 2016: e.T22679975A92836848. doi:10.2305/IUCN.UK.2016-3.RLTS.T22679975A92836848.en. Retrieved 13 November 2021.
Carboneras, Carles; Kirwan, Guy M. (2020-03-04). "Upland Goose (Chloephaga picta)". Birds of the World. Ithaca, New York, USA: Cornell Lab of Ornithology. Retrieved November 12, 2021.
Bulgarella, Mariana; Kopuchian, Cecilia; Giacomo, Adrián S. Di; Matus, Ricardo; Blank, Olivia; Wilson, Robert E.; Mccracken, Kevin G. (2014). "Molecular phylogeny of the South American sheldgeese with implications for conservation of Falkland Islands (Malvinas) and continental populations of the Ruddy-headed Goose Chloephaga rubidiceps and Upland Goose C. picta". Bird Conservation International. 24 (1): 59–71. doi:10.1017/S0959270913000178. ISSN 0959-2709.
Summers, Ronald W.; Grieve, Alastair (1982). "Diet, Feeding Behaviour and Food Intake of the Upland Goose (Chloephaga picta) and Ruddy-Headed Goose (C. rubidiceps) in the Falkland Islands". The Journal of Applied Ecology. 19 (3): 783. doi:10.2307/2403282. ISSN 0021-8901.
McDowall, R. M. (2004-12-23). "Falkland Islands biogeography: converging trajectories in the South Atlantic Ocean". Journal of Biogeography. 32 (1): 49–62. doi:10.1111/j.1365-2699.2004.01167.x. ISSN 0305-0270.
Gladbach, Anja; Gladbach, David Joachim; Kempenaers, Bart; Quillfeldt, Petra (2010-06-11). "Female-specific colouration, carotenoids and reproductive investment in a dichromatic species, the upland goose Chloephaga picta leucoptera". Behavioral Ecology and Sociobiology. 64 (11): 1779–1789. doi:10.1007/s00265-010-0990-4. ISSN 0340-5443. PMC 2952766.
Stang, D (2012). "Chloephaga picta (Magellan/Upland Goose)". ZipcodeZoo. Potomac Maryland: ZipcodeZoo.com. Retrieved 2013-02-17.
Summers, Ronald W. (1983). "The life cycle of the Upland Goose Chloëphaga picta in the Falkland Islands". Ibis. 125 (4): 524–544. doi:10.1111/j.1474-919x.1983.tb03146.x. ISSN 0019-1019.
Summers, Ronald W. (1983). "Moult-skipping by Upland Geese Chloëphaga picta in the Falkland Islands". Ibis. 125 (2): 262–266. doi:10.1111/j.1474-919x.1983.tb03110.x. ISSN 0019-1019.
Darwin, C (1859). "Difficulties on theory". On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life (Full image view 1st ed.). London: John Murray. pp. 171–206. {{cite book}}: External link in |edition= (help)
Pedrana, Julieta (2015). "FIRST INSIGHTS INTO THE MIGRATION PATTERN OF AN UPLAND GOOSE (CHLOEPHAGA PICTA) BASED ON SATELLITE TRACKING" (PDF). Neotropical Ornithology. 26: 245–253.
Bencke, Glayson Ariel; de Souza, Fabiano José (2013). "Upland goose Chloephaga picta (Anseriformes, Anatidae): First Brazilian record" (PDF). Revista Brasileira de Ornitologia. 21 (4): 292–294.
PEDRANA, JULIETA; BUSTAMANTE, JAVIER; RODRÍGUEZ, ALEJANDRO; TRAVAINI, ALEJANDRO (2011-05-23). "Primary productivity and anthropogenic disturbance as determinants of Upland Goose Chloephaga picta distribution in southern Patagonia". Ibis. 153 (3): 517–530. doi:10.1111/j.1474-919x.2011.01127.x. ISSN 0019-1019.
A Field Guide to the Wildlife of South Georgia; Princeton University Press 2012
Quillfeldt, Petra; Strange, Ian J.; Masello, Juan F. (2005). "Escape decisions of incubating females and sex ratio of juveniles in the Upland Goose Chloephaga picta" (PDF). Ardea. 93 (2): 171–178.
Cossa, Natalia A.; Fasola, Laura; Roesler, Ignacio; Reboreda, Juan Carlos (2018-09-01). "Incubating Upland Goose (Chloephaga picta) differential response to livestock, human, and predator nest disturbance". The Wilson Journal of Ornithology. 130 (3): 739. doi:10.1676/17-105.1. ISSN 1559-4491.
"Upland Goose". oiseaux-birds. Retrieved January 14, 2016.
Gorosábel, A.; Pedrana, J.; Bernad, L.; Caballero, V.J.; Muñoz, S.D.; Maceira, N.O. (2019). "Evaluating the impacts and benefits of sheldgeese on crop yields in the Pampas region of Argentina: A contribution for mitigating the conflicts with agriculture". Agriculture, Ecosystems & Environment. 279: 33–42. doi:10.1016/j.agee.2019.04.002. ISSN 0167-8809.
Darrieu, Carlos; Camperi, Aníbal; Imberti, Santiago (2008). "Avifauna (Non Passeriformes) of Santa Cruz province, Patagonia (Argentina): annotated list of species". Revista del Museo Argentino de Ciencias Naturales: 111–145. doi:10.22179/revmacn.10.296. ISSN 1514-5158.
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