Cygnus melancoryphus
Silhouette: Edwin Price · PhyloPic
In 3 days <5% in a week ~10%
The black-necked swan (Cygnus melancoryphus) is a species of waterfowl in the tribe Cygnini of the subfamily Anserinae. It is found in Argentina, Brazil, Chile, Uruguay, and the Falkland Islands. The black-necked swan has occasionally been placed by itself in the genus Sthenelides. Its closest relatives are the black swan (C. atratus) and mute swan (C. olor). It is monotypic.
The black-necked swan is the only member of its genus that breeds in the neotropics and is the largest waterfowl native to South America. Adults are 102 to 124 cm (40 to 49 in) in length. Its wingspan in winter averages 160 cm (5.2 ft), less at 136 cm (4.46 ft) in spring, due to loss of some primary feathers while moulting. Males weigh 4.6 to 8.7 kg (10 to 19 lb) and females 3.5 to 4.4 kg (7.7 to 9.7 lb). The black-necked swan is the lightest true swan on average. The sexes are alike. Adults' body plumage is white and the neck and head black; the latter usually has a white stripe behind the eye. They have a prominent red knob at the base of their bill. Juveniles are grayish rather than white and lack the knob until their third or fourth year. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Torres del Paine National Park | 🇨🇱 Chile | |
| 2 | Tierra del Fuego National Park | 🇦🇷 Argentina | |
| 3 | Península Valdés | 🇦🇷 Argentina | |
| 4 | Nahuel Huapi National Park | 🇦🇷 Argentina |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Buenos Aires | 🇦🇷 Argentina | |
| 2 | Montevideo | 🇺🇾 Uruguay |
Rare
Under 5% of wildlife watchers report a Black-necked Swan sighting in Nahuel Huapi National Park on a given day, based on 9 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 104th most-seen of the 111 birds we can rate there. Over three days the chance rises to under 5%, and over a week to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report a Black-necked Swan in Nahuel Huapi National Park on a given day, so our monthly data shows no clear season.
Between 3 and 6 pm
Across all the parks we cover, that three-hour window holds the most Black-necked Swan sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
4th of 4
Of the 4 parks where we can rate Black-necked Swan sightings, Nahuel Huapi National Park ranks 4th at under 5%. The best odds are in Torres del Paine National Park (Chile, about 20%), Tierra del Fuego National Park (Argentina, about 20%) and Península Valdés (Argentina, under 5%).
Same family: Anatidae
The closest relatives of the Black-necked Swan that you can see in Nahuel Huapi National Park (family Anatidae, Ducks, Geese, and Swans) are Ashy-headed Goose (about 40%), Yellow-billed Pintail (about 30%) and Flying Steamer-Duck (about 30%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Black-necked Swan is recorded against all the birds logged in Nahuel Huapi National Park (9 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
