Yellow-billed Teal (Anas flavirostris)

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Image of a Yellow-billed Teal in its natural habitat
Birds Teal

Introduction

The Yellow-billed Teal (Anas flavirostris) is a small dabbling duck of southern and western South America. It occupies a broad range of freshwater wetlands, from Andean lakes and high-altitude ponds to marshes, coastal wetlands and sheltered waters in the lowlands. The species is also known as the Speckled Teal in some sources, although Yellow-billed Teal is the accepted common name used here.

Physical Description

The Yellow-billed Teal is a compact duck measuring approximately 37–43 cm in length, with a wingspan of about 63–69 cm. Adults generally weigh around 390–430 g, with males tending to be slightly heavier than females.

Its plumage is predominantly brown, grey and buff, with fine dark spotting on the head, neck and breast. The upperparts are brown with darker feather centres and paler edges, while the underparts are relatively plain compared with the more heavily marked head and breast. The bill is typically yellow in the nominate southern form, although bills can be duller or bluish-grey in some Andean populations. The legs are generally yellowish to orange-brown.

Males and females are broadly similar in appearance, with limited sexual dimorphism. Males are usually somewhat larger, while females and juveniles tend to appear duller and less distinctly marked. Regional variation is noticeable, particularly in the colour of the bill, the darkness of the head and neck, and the density of the spotting.

Range and Habitat

The Yellow-billed Teal occurs across much of the southern half of South America. Its range includes Argentina, Chile, Uruguay, southern Brazil, Bolivia and Peru, extending southwards to Tierra del Fuego and the Falkland Islands. It has also established a breeding population on South Georgia, where it was first recorded breeding in 1971.

The species uses a wide variety of wetland habitats, including shallow lakes, marshes, swamps, ponds, slow-moving waterways and coastal or brackish wetlands. Andean populations occur in high-altitude lakes, ponds and páramo wetlands, while southern populations may use lowland freshwater habitats and coastal wetlands outside the breeding season.

Elevational range varies geographically. Some Andean populations occur at elevations of about 3,200–4,000 m, whereas other populations use wetlands near sea level. The species is partly migratory or locally mobile. Southern and highland birds may move to lower elevations or more northerly areas during colder periods, while other populations remain resident or make shorter seasonal movements.

Behaviour and Diet

Yellow-billed Teals are usually active during the day. They may occur singly, in pairs or in flocks, sometimes joining other waterfowl on suitable wetlands. Their flight is rapid and direct, and they often rise from the water with a quick burst of wingbeats.

They feed mainly by straining food from the water with the bill submerged, dabbling at the surface and up-ending to reach submerged material. Their diet includes aquatic plants, seeds, small crustaceans, insects and other aquatic invertebrates. The balance between plant and animal food varies with habitat and season. In South Georgia, observations recorded frequent feeding in ponds containing abundant small crustaceans.

Breeding behaviour varies among populations. The species is generally monogamous, and pairs may remain associated during brood care. Breeding commonly takes place during the austral spring, although timing differs across the range. Clutches generally contain about five to eight eggs, and incubation lasts approximately 24 days.

Nesting habits are geographically variable. Many Yellow-billed Teals nest on or near the ground in concealed vegetation close to water. In parts of Argentina, however, the nominate southern form regularly uses elevated sites, including cavities in abandoned stick nests of Monk Parakeets. Ducklings are precocial and leave the nest soon after hatching. Both parents may contribute to brood care, and young birds usually fledge at about six to seven weeks of age.

Identification Tips

Look for a small, compact brown duck with a noticeably yellow bill, fine spotting on the head and breast, and relatively subdued plumage overall. The species often swims low in the water and feeds by straining at the surface or tipping forward.

Useful field marks include:

  • A yellow bill, usually brightest in southern populations.
  • A brown, finely spotted head and neck.
  • A compact body and short-looking neck.
  • Relatively plain underparts compared with the spotted breast.
  • A dark green or purplish sheen in the speculum, visible in good light or during flight.

The Yellow-billed Teal can be confused with other small South American dabbling ducks, especially where ranges overlap. Bill colour, overall compact shape, head and breast spotting, and the absence of bold facial markings are useful when separating it from similarly sized teals. In South Georgia, its smaller size and more compact form help distinguish it from the larger South Georgia Pintail.

Conservation Status

The Yellow-billed Teal is listed as Least Concern on the IUCN Red List. It has a broad geographic range and remains locally common in parts of South America, but a precise global population estimate and a consistently documented population trend should not be assumed.

Potential threats include the loss, fragmentation and degradation of wetlands through agricultural expansion, drainage, pollution and changes in water management. Hunting may also affect some local populations. Climate-related changes to precipitation, water availability and high-altitude wetland conditions could create additional pressures, although the scale of these impacts requires further assessment.

Protection and restoration of freshwater and coastal wetlands, responsible water management, monitoring of hunted populations and continued surveys of Andean and subantarctic populations are important conservation measures.

Frequently Asked Questions

Where does the Yellow-billed Teal live?

It occurs across much of southern and western South America, including Argentina, Chile, Uruguay, southern Brazil, Bolivia and Peru. It also occurs in the Falkland Islands and on South Georgia.

Why is it called the Yellow-billed Teal?

The name refers to the yellow bill shown by many individuals, particularly in the southern part of the species’ range. Some Andean populations have duller or bluish-grey bills.

How large is a Yellow-billed Teal?

It is about 37–43 cm long, with a wingspan of approximately 63–69 cm. Males are generally slightly heavier than females.

What does the Yellow-billed Teal eat?

Its diet includes aquatic plants, seeds, small crustaceans, insects and other aquatic invertebrates. It commonly feeds by straining food from the surface and by up-ending in shallow water.

Does the Yellow-billed Teal migrate?

Movement varies between populations. Southern and high-altitude birds may move seasonally to lower or more northerly wetlands, while other populations are largely resident.

Where does the Yellow-billed Teal nest?

Nesting habits vary geographically. Some birds nest on the ground in concealed vegetation near water, while the southern form in parts of Argentina may use elevated cavities, including abandoned stick nests of Monk Parakeets.

References

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