Duck, Ruddy

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Description

The ruddy duck has a slightly different body shape than more familiar ducks like the mallard. It is smaller and more compressed, with a short thick neck and legs that are set further back on its underside. This leg position is fantastic for diving, but makes walking around on land rather awkward. As such, wild ruddy ducks spend most of their time in water, flying between different waterways and nesting in dense vegetation very close to the water’s edge.

Ruddy ducks display year-round sexual dimorphism in the form of a white cheek that is only present on males. During breeding season, this sexual dimorphism becomes more pronounced as males develop chestnut colored plumage on their backs, and the bills of these males turn a bright light blue. This blue bill color does not come from a pigment, but is the result of a phenomenon called structural coloration. As the breeding season starts, a hormonal change in male ruddy ducks causes microscopic changes in the outermost layer of their bill. These microscopic changes affect which wavelengths of visible light are absorbed and which are reflected back at our eyes—in this case, blue!

Cover Photo: Adult male and female ruddy ducks by John Burgess

Classification

Overview
The ruddy duck is a bird in the Anseriformes, or waterfowl order of birds. Its genus, Oxyura, is known as stiff-tailed ducks, due to their long, still tail that they often point upwards.
Class
Aves
Order
Anseriformes
Family
Anatidae
Genus
Oxyura
Species
O. jamaicensis

Key Facts

Conservation Status
Least Concern
Lifespan
up to 13 years in the wild, up to 20 years under human care
Height
1.1 – 1.4 ft (35 – 43 cm)
Weight
0.68 – 1.75 lbs (310 – 795 g)
Wingspan
1.7 – 2.0 ft (53 – 62 cm)

The IUCN Red List describes the ruddy duck as a species of Least Concern, meaning conservationists around the world are not currently worried about the continuation of this species. The current total population size is unknown—some sub-populations are decreasing, but some are stable and some have unknown trends. So far, the amount and rate of decrease is not enough to reclassify this species as Near Threatened.

Social Life
Ruddy ducks will migrate, forage, and roost in small flocks together. During courtship, males put on an elaborate display for females. This display involves hitting the underside of his beak against his chest, starting slowly and increasing frequency over a few seconds, and ending with a small call before repeating the process. During this, his stiff tail will be pointed upward.

Habitat and Range
Ruddy ducks prefer to spend their time on the water—this water can be marshes and swamps, pools and lakes, or lagoons and estuaries. They rarely leave the water in the wild, sleeping while floating and flying from one waterway to the next. Their nests are hidden in dense vegetation very close to the water’s edge.

Ruddy ducks are found in a massive range of latitudes of the Americas, as far north as the Northwest Territories of Canada, and as far south as the southern tip of Chile. In South America they are only present on the western coast, but in the US and Mexico they are widespread.

Diet
Ruddy ducks are omnivores. They eat a range of aquatic invertebrates, mainly insects but also molluscs, worms, and crustaceans, as well as the seeds of aquatic plants. They feed mostly by diving to the bottom of waterways and sifting through particulate, but will also dabble on the surface.

Predators
Ruddy ducks can dive under the water’s surface to escape predators, but they are still preyed upon by a variety of predators, including hawks, owls, minks, and foxes. Ducklings and eggs are also preyed upon by a variety of predators, including gulls, herons, and raccoons.

Reproduction
Sexual Maturity: 2 years, occasionally 1
Breeding/Nesting Season: starts April/May in northern range, year-round in coastal SA
Incubation: 25 – 26 days
Clutch Size: 5 – 15 eggs, usually 6 – 10

Information

Description

The ruddy duck has a slightly different body shape than more familiar ducks like the mallard. It is smaller and more compressed, with a short thick neck and legs that are set further back on its underside. This leg position is fantastic for diving, but makes walking around on land rather awkward. As such, wild ruddy ducks spend most of their time in water, flying between different waterways and nesting in dense vegetation very close to the water’s edge.

Ruddy ducks display year-round sexual dimorphism in the form of a white cheek that is only present on males. During breeding season, this sexual dimorphism becomes more pronounced as males develop chestnut colored plumage on their backs, and the bills of these males turn a bright light blue. This blue bill color does not come from a pigment, but is the result of a phenomenon called structural coloration. As the breeding season starts, a hormonal change in male ruddy ducks causes microscopic changes in the outermost layer of their bill. These microscopic changes affect which wavelengths of visible light are absorbed and which are reflected back at our eyes—in this case, blue!

Cover Photo: Adult male and female ruddy ducks by John Burgess

Classification

Overview
The ruddy duck is a bird in the Anseriformes, or waterfowl order of birds. Its genus, Oxyura, is known as stiff-tailed ducks, due to their long, still tail that they often point upwards.
Class
Aves
Order
Anseriformes
Family
Anatidae
Genus
Oxyura
Species
O. jamaicensis

Key Facts

Conservation Status
Least Concern
Lifespan
up to 13 years in the wild, up to 20 years under human care
Height
1.1 – 1.4 ft (35 – 43 cm)
Weight
0.68 – 1.75 lbs (310 – 795 g)
Wingspan
1.7 – 2.0 ft (53 – 62 cm)

The IUCN Red List describes the ruddy duck as a species of Least Concern, meaning conservationists around the world are not currently worried about the continuation of this species. The current total population size is unknown—some sub-populations are decreasing, but some are stable and some have unknown trends. So far, the amount and rate of decrease is not enough to reclassify this species as Near Threatened.

Social Life
Ruddy ducks will migrate, forage, and roost in small flocks together. During courtship, males put on an elaborate display for females. This display involves hitting the underside of his beak against his chest, starting slowly and increasing frequency over a few seconds, and ending with a small call before repeating the process. During this, his stiff tail will be pointed upward.

Habitat and Range
Ruddy ducks prefer to spend their time on the water—this water can be marshes and swamps, pools and lakes, or lagoons and estuaries. They rarely leave the water in the wild, sleeping while floating and flying from one waterway to the next. Their nests are hidden in dense vegetation very close to the water’s edge.

Ruddy ducks are found in a massive range of latitudes of the Americas, as far north as the Northwest Territories of Canada, and as far south as the southern tip of Chile. In South America they are only present on the western coast, but in the US and Mexico they are widespread.

Diet
Ruddy ducks are omnivores. They eat a range of aquatic invertebrates, mainly insects but also molluscs, worms, and crustaceans, as well as the seeds of aquatic plants. They feed mostly by diving to the bottom of waterways and sifting through particulate, but will also dabble on the surface.

Predators
Ruddy ducks can dive under the water’s surface to escape predators, but they are still preyed upon by a variety of predators, including hawks, owls, minks, and foxes. Ducklings and eggs are also preyed upon by a variety of predators, including gulls, herons, and raccoons.

Reproduction
Sexual Maturity: 2 years, occasionally 1
Breeding/Nesting Season: starts April/May in northern range, year-round in coastal SA
Incubation: 25 – 26 days
Clutch Size: 5 – 15 eggs, usually 6 – 10

adult female ruddy duck

Adult female ruddy duck by Mark Pressler