Coscoroba Swan Coscoroba coscoroba Scientific name definitions
- LC Least Concern
- Names (30)
- Monotypic
Text last updated September 7, 2013
Sign in to see your badges
Species names in all available languages
Language | Common name |
---|---|
Afrikaans | Coscoroba-swaan |
Bulgarian | Гъши лебед |
Catalan | cigne coscoroba |
Croatian | južnoamerički labud |
Czech | labuť koskoroba |
Danish | Coscorobasvane |
Dutch | Coscoroba |
English | Coscoroba Swan |
English (United States) | Coscoroba Swan |
Finnish | ankkajoutsen |
French | Coscoroba blanc |
French (France) | Coscoroba blanc |
German | Coscorobaschwan |
Japanese | カモハクチョウ |
Norwegian | coscorobasvane |
Polish | koskoroba |
Portuguese (Brazil) | capororoca |
Portuguese (Portugal) | Capororoca |
Russian | Коскороба |
Serbian | Koskoroba labud |
Slovak | koskoroba biela |
Spanish | Cisne Coscoroba |
Spanish (Argentina) | Coscoroba |
Spanish (Chile) | Cisne coscoroba |
Spanish (Paraguay) | Coscoroba |
Spanish (Spain) | Cisne coscoroba |
Spanish (Uruguay) | Coscoroba |
Swedish | coscorobasvan |
Turkish | Koskoroba Kuğusu |
Ukrainian | Коскороба |
Coscoroba coscoroba (Molina, 1782)
Definitions
- COSCOROBA
- coscoroba
The Key to Scientific Names
Legend Overview
Introduction
The smallest species of swan, Coscoroba Swans are still one of the largest species of waterfowl in South America. They inhabit swamps, lakes, lagoons and other bodies of fresh water in southern South America. This species is a partial migrant, breeding in southern Chile and Argentina south to Tierra del Fuego, and then moving north in winter; the bulk of the population winters in central and northern Chile and Argentina and Uruguay, with individuals make it as far north southeastern Brazil. There is also a population on the Falkland Islands.
Coscoroba Swans are more goose-like in appearance than their Northern Hemisphere relatives. Both sexes are all white, with black wingtips and red bills and legs. The Coscoroba Swan is one of only two all-white waterfowl in South America. The other all-white species, the male Kelp Goose Chloephaga hybrida, is much smaller, inhabits rocky coastlines, and lacks the red bill and legs of the Coscoroba Swan.
Though its population was estimated at around 100,000 individuals, BirdLife International has listed the Coscoroba Swan as a species of Least Concern; habitat destruction and degradation through the diversion of wetlands are the chief threats to this species.
Field Identification
90–115 cm; male 3800–5400 g, female 3100–4500 g (1). The smallest swan. Black tips to six outermost primaries . Breast feathers appear centrally parted. Female has brown iris and is smaller than male (wing 415–477 mm versus 440–498 mm in male) (1). Juvenile similar to female, but brownish on head and upperparts , before developing adult plumage by eight months old (1); bill blue-grey (1); bare-parts coloration much like adult by five months (1). S birds apparently larger than those in N, e.g. in S Brazil, wing of male is just 375–390 mm (1).
Systematics History
Subspecies
Distribution
S South America from Tierra del Fuego and Falkland Is N to C Chile and N Argentina; winters N to Paraguay, SE Brazil and probably in Bolivian Chaco, where recently recorded (2).
Habitat
Favours lagoons and large freshwater swamps, preferably those with well-vegetated margins, but has also been recorded at man-made reservoirs (3). Occurs mainly in lowlands with scattered breeding records to 1300 m and one at 2000 m in NW Argentina (Tucumán) (3), and the species has occasionally been recorded up to 1000 m in Andean foothills of Santa Cruz (S Argentina) (1).
Movement
Some southern breeders migrate to lower latitudes (c. 25º S) in winter, exceptionally N of the Tropic of Capricorn, but other populations usually considered to be mainly sedentary, including those in Magellanic region and NW Isla Grande is considered an important wintering area (1). However, in neighbouring Chile, where the species was formerly considered rare winter visitor in early 20th century (1), the species is now mainly a winter visitor to C Chile, breeding in S of country (4). Marked movement, with Cygnus melanocoryphus, into Uruguay during 1988/89 was attributed to drought further S, mostly from Argentina (1). Long-term banding study (involving 1070 birds) in S Brazil has revealed heretofore unsuspected level of movements, including one bird that was recovered in Chubut, S Argentina (04º S), although it seems that males are perhaps more faithful to their natal area, but juveniles are clearly capable of widespread dispersal prior to their achieving sexual maturity (5). Although occasionally breeds in Falklands (c. 1860, display observed Nov 1994) (6), mainly a visitor to the islands, sometimes in small flocks (7), with an influx noted in Nov 1998 (1). Vagrants have been recorded several times outside usual range in Brazil, in Santa Catarina (one undated, the other records in 1978, 1990 and 1991) (8), several times (including large flocks) in Paraná (1990 (9), 1996, 2002, 2003) (10) and three times in Mato Grosso do Sul (in 1988–1990) (11), while there is one confirmed record in Bolivia , in Departamento Santa Cruz, in Jul 2006 (12).
Diet and Foraging
Apparently varied diet (but no detailed studies), consisting of plant matter, small aquatic and marine (1) invertebrates, fish spawn, etc. Forages mainly in shallow water, by swimming and dabbling or wading, but also grazes on land; does not upend as frequently as other swans (1). Regularly forms mixed flocks with Cygnus melanocoryphus (1).
Sounds and Vocal Behavior
Onomatopoeic “cos-cor-oo” is usually given in threat display against intruders (but is not accompanied by “Triumph Display” typical of other swans), and also a monosyllabic hooting note, often uttered by male and female alternately, is used in contact; notes are similar in the sexes, but are noticeably higher-pitched in the male (whereas in most swans it is females that are higher-pitched), while immatures give loud chirps and trills (1).
Breeding
During local spring; May–Oct in NW Argentina (3), Jul–Dec in Chile (13), Jul–Aug in S Brazil (1), or May–Dec over entire breeding range (i.e. one month earlier on average than C. melanocoryphus) and young hatch as late as Feb in C Chile (1). Monogamous and usually forms long-term pair-bonds (1), although extra-pair copulations were observed twice in one recent study (13). Usually in single pairs, though nests sometimes just 10–18 m apart (13) in prime habitat and occasionally breeds within C. melanocoryphus colonies (1); nest is large mound of aquatic vegetation (sometimes mainly constructed by male) (1) well lined with soft grasses and down situated on small islands, in reedbeds or in long grass, close to water, and pairs sometimes build multiple nests (13), although may re-use same nest in subsequent seasons (3); territory size in C Chile c. 0·25–7 ha (13). In NW Argentina, nests were close to (within c. 1–7 m) the shoreline, in water 12–50 cm deep, on marshy soil, of mud and aquatic plants (Ludwigia longifolia, Myriophyllum quitense), and mean nest height was 33·4 cm above water level, mean cup diameter was 33·6 cm and depth 13·9 cm; basal length was 78·4 cm and width 77·5 cm; nests were sometimes used by Andean Coot (Fulica ardesiaca) after they were abandoned by the swans (3). Apparently double-brooded in S Brazil and C Chile, where second clutches initiated when first broods are 40–50 days old (1). Clutch 4–9 eggs , white, size 82–94·5 mm × 52·9–67 mm, mean mass c. 167 g (captivity) (1); incubation c. 35 days by female alone guarded by male (1); downy chicks mainly greyish white with three drab grey dorsal bands and black cap , grey bill with pink tip and pale pink feet tinged grey (1), cared for by both adults and fledge at 13 (captive) or c. 14 weeks (wild birds) (1), and only reach adult size at c. 8 months, but sometimes remain with adults until 12 months old in C Chile (13), even into second year in captivity (1). Newly hatched young may be predated by Kelp Gulls (Larus dominicanus) (13). Breeding success unknown, but mean brood size 5·32 in C Chile, with one case of brood amalgamation noted (and this phenomenon may be comparatively frequent) (13). Adult survival in captivity up to 20 years (mean 7·3 years), while normal age of first breeding is unknown in wild, captive birds can breed when just one year old, more frequently at three years (1).
Conservation Status
Not globally threatened (Least Concern). CITES II. Still widespread and quite common locally, with an overall population estimated at < 25,000 birds in late 1990s (1); thought to be decreasing in some areas, especially in Chile, where listed as Endangered (1) and may now be largely restricted as a breeder to extreme S , with total population reckoned at under 1000 birds in 1970s, although some 1000–2000 individuals were off Puerto Natales, S Chile, in Apr (late autumn) (14) and the local population at El Yali, C Chile, was estimated at 230–250 birds in Jul 2002 (c. 34% breeding pairs with territories, 29–33% non-territorial pairs and 33–38% mostly groups of young birds) (13). Partial census of Jul 1990 gave 350 in Uruguay and 12,195 in Argentina, while partial census in May to early Jun 1998 of wetlands in Argentina and Uruguay found total of 4036 birds (1). Large numbers occur in N of Isla Grande (Tierra del Fuego), but is far less common than sympatric <em>Cygnus melanocoryphus</em> , and in neighbouring Santa Cruz province, Argentina, is known from several protected areas (15). Brazilian population very poorly known, but suspected to be in danger of extinction (1). In Paraguay mainly confined to Chaco region (16), while in SE Uruguay population estimated at up to 500 birds, including breeding pairs (1). Greatest threat seems to be loss of temperate marsh habitats due to urbanization and agricultural developments, especially as range always seems relatively patchy, and hunting never appears to be have been a significant threat (1), although it has been observed within protected areas in Chile (13).