Torrent Duck

BirdSouth America

21 Sept

Merganetta armata

The torrent duck is highly adapted for hunting within the fast-flowing rivers of the Andes — it kicks with powerful webbed feet, its long claws cling to slippery rocks, and its sleek body allows it to scale waterfalls. Even chicks, soon after hatching, plunge into the dangerous currents.

The peaks of the Andes thrust into the heavens, nearly reaching heights of 7,000 metres (22,965 ft). ¹ A trek up these mountains is a journey from lush tropical forests to barren domains of dark rock cloaked in seasonal snow and permanent glacial ice. But these highlands, desolate as they are, provide for much of the rich life in the lands below. As ice caps thaw and melt and glaciers gush, their waters have nowhere to flow but downwards. Trickling down the mountainsides, disparate streams converge onto paths of least resistance, forming torrential rivers that race down steep slopes and cascade in crashing waterfalls. These icy, impetuous waterways don't seem very suitable for life, but a few bold species make their living here — clinging to the river rocks, battling the tumbling falls, and plunging beneath the churning torrents. ²

The Daredevil Duck

The torrent duck may lead the most extreme lifestyle of any waterfowl. From Venezuela to Tierra del Fuego, the torrent duck's range traces the skinny Andes range. It lives in areas of steep mountain slopes and rigid rock walls — at altitudes of 1,500 to 4,800 meters (4,920 - 15,750 ft) — between which flow some of the fastest and most powerful rivers in the Andes. These waterways are the fleeing progeny of snow and ice, birthed from peaks several thousand metres above.

A torrent duck is often seen standing stoically on a rock amidst tumultuous waters, clinging to the slippery surface with long-clawed toes. Its body is small and sleek. It slides into the rushing river, kicking with its large and powerful webbed feet, swimming against the current with seemingly no effort at all. Then it upends its body; its head disappears below the water as its tail sticks straight into the air. Its long tail feathers act to balance its body while, beneath the water, it probes under rocks with its narrow red bill.

It's searching for the larvae of aquatic insects — stoneflies, mayflies, and caddisflies — or hiding molluscs and crustaceans. If its bill can't extract its quarry, the duck flips back over and paddles at its prey with its feet, kicking the helpless critters up into the current. Or, the torrent duck may let the river itself flush out a meal. A waterfall supplies an outpouring of tumbling creatures as it spills over its ledge. If one can withstand the pounding cascade of water — and the torrent duck can — they gain access to a wild, ever-changing buffet. Once the duck has eaten its fill, it dashes up the waterfall and flies low over the water to a new section of the river. And if it ever encounters danger, it simply dives beneath the churning currents, invisible and out of reach.

Duck Romances: Chaotic & Loyal

Torrent ducks are often seen in pairs; monogamous couples that bond for life. The female wears a cap of grey plumage that flows into her grey-black wings and barred tail feathers. Her breast and underbelly, however, are a bright cinnamon-red. The male's body is a striped motley of bland browns, greys, and blacks — with iridescent green bars at the base of each wing — but to compensate for this lack of pomp, he wears an elaborate mask of bright white, streaked with lines of black that split and converge like mountain streams.

The male calls to his mate with a cry like a high-pitched whistle, carrying over the racket of the river. The female responds with a deeper, booming quack. The two hold territory over a portion of the river, with the male warding off invaders using the long spurs on his legs. Their nest is made anywhere along their stretch of water; in dense vegetation, a tree stump, deep crevice, cave, or on a cliff above the river — precariously placed up to 18 metres (60 ft) up the cliff face.

In the nest-cup, woven from dry grasses and lined with fluffy down feathers, the female lays her clutch. Depositing the 3 - 4 eggs is a huge load off the soon-to-be mother, as they've grown to half her own body weight by the time she lays them. But she still has a job ahead of her — incubating the eggs for about 43 days — but at least the male is there for support. If he's not, if the father has waddled off somewhere, she refuses to return to their clutch and won't incubate them unless he's by her side. The long incubation gives the chicks additional time to develop, and a head-start when they hatch. They emerge covered in downy plumage, patterned in swirls of black on white. They are small — only about 35 grams (1.2 oz) each — but they're also hardy. And they have to be, for they're immediately thrust into a world of dizzying heights and crashing cold waters.

An Intense Upbringing

Violent, frigid mountain rivers don't seem the best environment for raising a family. The torrent duck disagrees. Torrent duck chicks don't enjoy a gentle childhood; their introduction to aquatic life is far from the idyllic slow waddle into a pond, safely trailing after mom. Instead, soon after the torrent ducklings hatch — wide-eyed, experiencing the world for the very first time — they are commanded to leave the soft, warm comfort of their nest and plunge into the cold waters below. Their mother leads by example; she drifts atop the river beneath the nest and calls to her chicks, repeatedly and insistently, that they come join her.

The ducklings leap from their lofty roost, falling gracelessly and often slamming against rocks and vegetation on their way down the cliff face. Luckily, their small size and fluffy feathers cushion them in their descent, and they plop into the water quite unharmed. Now comes the true test; they must navigate the rushing river. Here, the parents do at least help them by keeping the chicks between themselves and the shore, where swimming is less challenging. And, if a duckling gets caught in the flow and snatched downriver, both parents will chase after the chick to save it.

¹ The tallest mountain in the Andes, Aconcagua, stands at 6,961 metres (22,840 ft) tall. The Andes range itself stretches some 8,900 kilometres (5,500 miles) along the west coast of South America — from the northernmost coast of the Caribbean to the continent's southern tip — making it the longest mountain range in the world (if not the widest).

Clockwise from top left; a white-capped dipper (*Cinclus leucocephalus*), a torrent tyrannulet (*Serpophaga cinerea*), Andean catfish (*Astroblepus ubidiai*), and southern river otter (*Lontra provocax*).

² The torrent duck isn't the only creature that braves the rushing rivers of the Andes. Throughout the northern half of the Andes, the white-capped dipper — a small, compact, black-and-white bird — hops across riverine rocks, occasionally dipping beneath the water, as it hunts for the same prey as the torrent duck. The torrent tyrannulet is similarly small, plump, and monochrome. It shares the dipper's range and riverside habits but is more hesitant to get itself wet. Beneath the river surface lives the Andean catfish. Only found in mountain rivers of the Ecuadorian Andes, it is considered critically endangered. Meanwhile, down in the southern Andes lives the endangered southern river otter — inhabiting the smallest geographical range of any otter species. Despite being a lithe aquatic hunter, it prefers taking life at a slower pace; living in calmer rivers, or even lakes and lagoons, where it catches and crunches on its favourite snacks; crabs and crayfish.

The Loa River of Chile
Eventually, the rivers borne from icy peaks reach the lowlands, where their crashing momentum is slowed to a placid slide. Although the torrent duck thrives above altitudes of 1,500 metres (4,920 ft), it can be seen near sea level in parts of Chile. In Chile, the longest river is the Loa. It begins its journey in the Andes, at the base of Miño Volcano (more than 4,000 metres, or 13,000 ft, above sea level). It flows through the country in a dipping curve. Throughout its course, it provides water for drinking and irrigation in dry desert areas, as well as generating hydroelectric power for the country's industries, before flowing out to sea.
The Magdalena of Columbia
To the north in Columbia, some 3,685 metres (12,000 ft) up in the Andes, lies the Magdalena Lagoon. This lagoon spawns the country's most important river. The Magdalena, flowing northwards through Columbia, accounts for 70% of the country's hydroelectric energy and 90% of its thermo-electric power, as well as providing 38 million people with drinking water. Its waters and surrounding habitats also hosts more than 150 mammal species (e.g. West Indian manatee and brown spider monkey), more than 630 bird species (e.g. harpy eagle and northern screamer), more than 120 reptile species (e.g. Magdalena river turtle and spectacled caiman), more than 50 amphibian species (e.g. golden poison dart frog and Magdalena giant glass frog), and more than 120 fish species (e.g. bocachico and the Capitán de la Sabana). Many of the species are found only along the Magdalena River.
The Amazon River
The Amazon, the greatest river in South America and perhaps the most famous in the world, hardly needs an introduction. The waters that converge to form this massive aquatic highway originate in the high Peruvian Andes; 5,598 m (18,360 ft) above sea level. This river is the world's largest drainage system, containing some 20% of the world's flowing fresh water. And, as the Andes gives birth to the Amazon River, the Amazon River creates and nurtures the largest rainforest in the world. Not only does this river-born forest provide people (locals and the world at large) with food, water, and medicine, but it's also one of the main stabilisers of the climate.
Varied habitats, from swamps to marshes to streams, stem from the Amazon River, each hosting vast and varied menageries of life. The biodiversity of its rainforest is nothing short of legendary and a recounting of its wildlife (what we know of it at least) could fill a library of books. But I think a few species, intrinsically linked to the river, are worth mentioning.
Enigmatic fish lurk beneath the river's turbid waters. The giant, hunched arapaima — among the world's largest freshwater fish — often surfaces to take large gulps of air. Electric eels, possessing the voltage to stun a horse, slither through murky pools and lagoons. Several tens of piranha species swarm in shoals, snapping at prey with their rows of sharp teeth and underbite jaws — their reputation as strippers of human flesh, however, is exaggerated, as they rarely attack humans and incidents of death from piranha attacks are very few.
The green anaconda, the heaviest snake on Earth (weighing up to 250 kg, or 550 lbs), is slow on land, but surprisingly swift in the water. It rises from streams like a sea serpent, grabbing its prey — writhing, coiling, and constricting — until all breath has left its victim's lungs.
The Amazon River also hosts creatures of the warm-blooded kind. The Amazon river dolphin (a.k.a. the boto) manoeuvres through mangroves and murky waters using whisker-like receptors on its snout. It also goes by the descriptive name of "pink river dolphin", and although the reason for its pinkness isn't known, it appears to become pinker as it ages. Herds of Amazonian manatees graze on subaquatic fields of "water cabbages" and other vegetation, like gatherings of tubby, floating cows. And giant river otters, reaching lengths of up to 1.8 metres (5.9 ft), hunt the Amazon's waterways for fish, while emitting purrs, squeals and loud screams.
From the black caimans to the capybaras that live in the waters, to the monkeys that swing along tree branches and the hoatzin that clambers through them, to kingfishers and parakeets in the skies above; the Amazon River, and the rainforest it cultivates, is home to over 5,500 animal species and that's not including the upwards of 100,000 invertebrates, or all the species we've yet to discover.

**Where Does It Live?**

⛰️ Near fast-flowing and powerful mountain rivers.
📍 Throughout the Andes Mountains; from Venezuela in the north to Tierra del Fuego in the south.

‘Least Concern’ as of 01 October, 2016.

IUCN

Size // Small
Wingspan // N/A
Length // 43 – 46 centimetre (17 – 18 in)
Weight // 320 – 480 grams (11 – 17 oz)
Activity: Diurnal ☀️
Lifestyle: Social / Pair 👤/👥
Lifespan: Up to 18 years (in captivity)
Diet: Carnivore
Favorite Food: Aquatic invertebrates 🐌
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Merganetta
Species: M. armata

The torrent duck will build its nest on tall cliff faces — up to 18 metres (60 feet) above a river.
Soon after torrent ducklings hatch, their mother calls to them from the river below. They waddle to her voice and fall from their nest — often smacking into rocks and vegetation on their way down to the water.
Luckily, the ducklings' small size and their fuzzy feathers protect them during their tumble.
In the water, both parent ducks help their chicks to swim by keeping them near the river banks, and if a chick is swept backwards in the current, both parents will follow to save it.
The male torrent duck exhibits fancy facial markings of flowing black over white, while the female has a cinnamon-red underside. The chicks are covered in fluffy down and patterned in black and white.
The range of the torrent duck traces the skinny range of the Andes Mountains; from Venezuela in the north to Tierra del Fuego in the south.
It typically lives at altitudes between 1,500 and 4,800 meters (4,920 - 15,750 ft), in areas with steep mountain slopes and fast-flowing rivers.
This duck swims against the powerful river current with seemingly no exertion and it can even scale waterfalls. It doesn't fly much, but when it does, its flight is low to the water and short.
It hunts for crustaceans, molluscs, and the larvae of aquatic invertebrates by flipping upside down and probing under rocks with its narrow red bill. If that doesn't work, it flips back over and kicks at its prey with its powerful webbed feet in order to unlodge it.
While torrent duck chicks are small when their born — only weighing some 35 grams (1.2 oz) each — the entire clutch of 3 to 4 eggs can weigh half as much as the mother when she lays them.
Males and females are monogamous and pair for life. The female does all the incubating, but if the male isn't there to support and defend her, she will abandon their clutch of eggs.
The torrent duck isn't known to have many predators — due to the turbulent and inaccessible nature of its river habitat. Likely, the only predators to hunt this duck are large fish that feed on swimming chicks.
It is, however, vulnerable to humans. It is sometimes hunted and, especially in its northern range, it is disappearing from some rivers due to pollution, deforestation, erosion and overfishing.
The torrent duck is the only species within its genus (Merganetta).
For now, it is considered a species of 'least concern' by the IUCN.