Eaton's Pintail Anas eatoni Scientific name definitions

35–45 cm, male 430–502 g, female 400–500 g#R, wingspan 65–70 cm. Compared to A. acuta (with which previously considered to be conspecific, see Taxonomy comments), A. eatoni  (the only duck, other than introduced A. platyrhynchos, in range) is much smaller with much less marked dimorphism; only a few males (c. 1% of population) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ) show something of the pattern of A. acuta; normally very brown, with buffer and more cinnamon underparts, and like female, although separable by green, not brown, speculum, slightly elongated central rectrices and more obvious black culmen (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Juvenile generally also female-like, but differs in being more streaked below, while young males swiftly acquire a more brighter speculum (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Race drygalskii is poorly differentiated from nominate eatoni, although has less conspicuously barred underparts, longer tarsus (mean c. 36 mm, versus c. 35 mm in eatoni) and culmen (mean c. 34·5 mm, versus c. 34 mm), and shorter wings (mean c. 212 mm, versus c. 234 mm) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Editor's Note: This article requires further editing work to merge existing content into the appropriate Subspecies sections. Please bear with us while this update takes place.

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Inhabits small freshwater lakes, as well as pools, marshes, peatbogs and streams. Both nominate and drygalskii mainly frequent sheltered coastal bays in winter (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Mainly sedentary, though most of population move to coastal areas in winter, only small numbers remaining on ice-free lakes inland (3 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ), but with little evidence of movement between the Kerguelens and Crozets (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Vagrant to Prince Edward Is (4 Ausilio, E. and Zotier, R. (1989). Vagrant birds at îles Kerguelen, southern Indian Ocean. Cormorant. 17: 9–18. Close ).

Primarily feeds diurnally, in small groups (occasionally up to 200) (3 Shirihai, H. (2007). A Complete Guide to Antarctic Wildlife. The Birds and Mammals of the Antarctic Continent and the Southern Ocean. Second edition. A. & C. Black, London, UK. Close ), taking animal matter (crustaceans and moist-soil invertbrates) as well as seeds, but occasionally also at night, especially while moulting, and visits elephant seal (Mirounga leontina) wallows to forage (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Vocalizations of both sexes are said to resemble those of A. acuta, but are slightly higher-pitched and quieter, while duckling calls are reportedly very quiet (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

Laying season Nov–Mar, with young mainly hatching in Feb (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Mating system unknown, but usually observed in pairs in austral spring (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Usually in single pairs, sometimes up to 500 m above sea-level; nest constucted in tussock or grass, lined with moss and down, sometimes in rock cleft (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Usual clutch five pale olive-green eggs (range 2–6), size 52–56 mm × 36–39 mm, mass 40·1 g (in captivity); incubation period unknown, by female alone; ducklings similar to those of A. acuta, but smaller, paler above, with reddish-buff dorsal spots, more rufous tones to face, breast and underparts, and has less distinctly marked face, weigh 25·7 g when one day old (in captivity); no data on fledging period, but young tended by female alone for unknown period (probably abandoned comparatively early, whereafter still-flightless young gather into large groups) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Predators include Brown Skua (Catharacta antarctica) (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Few data on breeding success, but clutches of c. 3·9 eggs reduced to broods of 3·2 young shortly after hatching and c. 1·8 at day 20 (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ). Probably achieves sexual maturity at c. 1 year old, but no data on annual adult survival or longevity (1 Kear, J., Editor (2005). Ducks, Geese and Swans. Volume 1: General chapters, and Species accounts (Anhima to Salvadorina). Oxford University Press, Oxford, UK. Close ).

VULNERABLE. Currently estimated joint population of 31,200–41,400 mature individuals that is thought to be in decline. In Crozet Is, subspecies drygalskii estimated at 1350 birds (800 on Est I) in 1980–1982, rare on some islands due to introduction of cats and rats last century. Nominate eatoni distributed throughout Kerguelen I and outlying islands, but only abundant in lowlands, estimated 5000–10,000 pairs in 1982–1985, suffering annual losses of 200–300 through hunting by sealers and scientific expeditions; today, introduced predators are greatest threat on Possession, Cochons Island (Crozet) and Kerguelen Is, where feral cats may prove to be serious threat in near future if petrels, their staple prey, reach low sufficiently levels. Failed to become established on Amsterdam I, where introduced but not seen since 1970, due to predation by cats and rats (Rattus norvegicus); at present, population appears stable.