Duck, Wood

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Description

The male wood duck is unmistakable in breeding plumage. Males have a bright red eye and greenish-purple iridescent feathers on their head that give the appearance of slicked-back hair. The rest of their plumage is large sections of tans, browns, and iridescent blues and purples, separated by bold black and white lines. They also have a colorful orange, yellow, white, and black bill.

Wood ducks are a fantastic example of sexual dimorphism, and females are much less conspicuous than males. Females exhibit countershading, with a woody brown color on their upper sections, mottled brown and white on their mid sections, and a white belly. They also have a bold white eye ring around their eye and a patch of iridescent purplish-blue speculum feathers on their wings.

Males use their extravagant colors to attract females, while the females are able to camouflage into their woodland habitat and nesting hollows better with their more modest attire. Male wood ducks are more likely to attract predators with their bright plumage, so they molt their feathers twice a year and switch between two different sets of plumage: breeding plumage for the breeding season, and eclipse plumage for the rest of the year. Males in eclipse plumage look much more similar to females, but can still be distinguished by their red eyes and multicolored beaks.

Cover Photo: Adult male & female wood ducks by Mark Pressler

Classification

Overview
The wood duck is a bird in the Anseriformes, or waterfowl order. The only other duck that shares the genus Aix is the mandarin duck, another woodland duck with extravagantly colored males.
Class
Aves
Order
Anseriformes
Family
Anatidae
Genus
Aix
Species
A. sponsa

Key Facts

Conservation Status
Least Concern
Lifespan
Oldest recorded wild wood duck was 22.5 years old. Average lifespan is significantly less, likely ~3 – 5 years
Height
1.4 – 1.7 ft (43 – 51 cm)
Weight
1.06 – 1.94 lbs (482 – 879 g)
Wingspan
2.3 – 3.2 ft (71 – 99 cm)

The IUCN Red List currently classifies the wood duck as a species of Least Concern, meaning conservationists across the world are not currently worried about the continuation of this species. However, this was not always the case—wood ducks are a great example of how conservation action can help a species recover from rapid decline.

In the late 1800s and early 1900s, wood ducks were hunted extensively for both food and fashion—in fact, in the early 1900s, wood ducks may have been the most hunted waterfowl species in the United States. This, combined with habitat loss from the logging of hardwood forests, was enough to cause a noticeable and significant decline in their population numbers. Because of their secretive nature and dense woodland habitat, it’s extremely difficult to get an accurate understanding of how low their numbers dropped, but bird experts at the time saw enough of a decline that they were worried about losing wood ducks completely.

In 1918, the Migratory Bird Treaty Act was passed in the US, which provides protection for more than 1,000 different migratory birds, including the wood duck. Through this regulation of hunting as well as protection of some of the important habitat for wood ducks, their numbers started to rebound in the 1920s. In the 1930s, wood ducks received another major boost with the development of the artificial nesting box. Wood ducks are cavity nesters, historically nesting in tree hollows near waterways. However, they seemingly have no issue nesting in properly sized and placed human-made nest boxes. As both scientists and duck enthusiasts placed these boxes in wood duck habitat, the bottleneck of nesting location was effectively removed and wood duck numbers significantly increased.

Currently, wood duck population numbers are stable and large, with an estimated 4.6 million individuals in the wild. This duck is a fantastic example of how both protection through policy and a little bit of reproductive assistance can go a long way in the recovery of a species.

Social Life
Male wood ducks will pair with a single female for a breeding season, but usually pair with a new female the next season. They are fairly social birds, and often roost and migrate in pairs or small flocks.

Nesting females have a fascinating behavior called conspecific brood parasitism. This means that sometimes a female will seek out her own nesting hollow or nest box and lay her eggs there, but sometimes will find other females’ nests to lay her eggs in. Scientists are still unsure of what exactly prompts females to make this decision—there is certainly a benefit to continuing your genetic lineage without needing to rear any chicks yourself, but the more females that decide to forgo having their own nest, the less nests are available for parasitism and the worse of a decision that becomes. This leads to complex nesting behavior—it may be advantageous for females to be especially secretive when entering and leaving their nests, not just because of predation risk but to prevent other females from discovering the nest location and laying their eggs there. “Dump nests” of more than 50 unincubated eggs have been found, perhaps these are formed when too many females learn about a nesting location and the original eggs become crushed under the weight of new eggs, leading to abandonment of the nest.

Wood ducklings are highly precocial, meaning they are capable of moving around the world and feeding themselves soon after birth. These ducklings typically leave the nest within the first day after they are born. Because they nest up in tree hollows or nest boxes, they must make a leap of faith down to the forest floor together, before following their mother to the nearest waterway.

Habitat and Range
Wood ducks migrate up and down all 4 of the major flyways in North America: the Pacific Flyway, Central Flyway, Mississippi Flyway, and Atlantic Flyway. They move between Canada and the northern US, to Mexico, Cuba, and the southern US.

Wood ducks spend their time in freshwater pools, lakes, and waterways, preferably with dense surrounding woodland vegetation.

Diet
Wood ducks are omnivores, eating nuts, namely acorns, seeds, and various aquatic plants, as well as a variety of invertebrates.

Predators
Wood ducks and their ducklings are often preyed upon by owls, minks, raccoons, foxes, alligators, and snakes. Ducklings have even more predators, and due to their highly precocial nature, they are extremely vulnerable for the first few months of their life.

Reproduction
Sexual Maturity: ~1 year
Nesting Season: ~February – June
Incubation: ~1 month
Clutch Size: highly variable due to conspecific nest parasitism, but typically ~10 – 20 eggs.

Information

Description

The male wood duck is unmistakable in breeding plumage. Males have a bright red eye and greenish-purple iridescent feathers on their head that give the appearance of slicked-back hair. The rest of their plumage is large sections of tans, browns, and iridescent blues and purples, separated by bold black and white lines. They also have a colorful orange, yellow, white, and black bill.

Wood ducks are a fantastic example of sexual dimorphism, and females are much less conspicuous than males. Females exhibit countershading, with a woody brown color on their upper sections, mottled brown and white on their mid sections, and a white belly. They also have a bold white eye ring around their eye and a patch of iridescent purplish-blue speculum feathers on their wings.

Males use their extravagant colors to attract females, while the females are able to camouflage into their woodland habitat and nesting hollows better with their more modest attire. Male wood ducks are more likely to attract predators with their bright plumage, so they molt their feathers twice a year and switch between two different sets of plumage: breeding plumage for the breeding season, and eclipse plumage for the rest of the year. Males in eclipse plumage look much more similar to females, but can still be distinguished by their red eyes and multicolored beaks.

Cover Photo: Adult male & female wood ducks by Mark Pressler

Classification

Overview
The wood duck is a bird in the Anseriformes, or waterfowl order. The only other duck that shares the genus Aix is the mandarin duck, another woodland duck with extravagantly colored males.
Class
Aves
Order
Anseriformes
Family
Anatidae
Genus
Aix
Species
A. sponsa

Key Facts

Conservation Status
Least Concern
Lifespan
Oldest recorded wild wood duck was 22.5 years old. Average lifespan is significantly less, likely ~3 – 5 years
Height
1.4 – 1.7 ft (43 – 51 cm)
Weight
1.06 – 1.94 lbs (482 – 879 g)
Wingspan
2.3 – 3.2 ft (71 – 99 cm)

The IUCN Red List currently classifies the wood duck as a species of Least Concern, meaning conservationists across the world are not currently worried about the continuation of this species. However, this was not always the case—wood ducks are a great example of how conservation action can help a species recover from rapid decline.

In the late 1800s and early 1900s, wood ducks were hunted extensively for both food and fashion—in fact, in the early 1900s, wood ducks may have been the most hunted waterfowl species in the United States. This, combined with habitat loss from the logging of hardwood forests, was enough to cause a noticeable and significant decline in their population numbers. Because of their secretive nature and dense woodland habitat, it’s extremely difficult to get an accurate understanding of how low their numbers dropped, but bird experts at the time saw enough of a decline that they were worried about losing wood ducks completely.

In 1918, the Migratory Bird Treaty Act was passed in the US, which provides protection for more than 1,000 different migratory birds, including the wood duck. Through this regulation of hunting as well as protection of some of the important habitat for wood ducks, their numbers started to rebound in the 1920s. In the 1930s, wood ducks received another major boost with the development of the artificial nesting box. Wood ducks are cavity nesters, historically nesting in tree hollows near waterways. However, they seemingly have no issue nesting in properly sized and placed human-made nest boxes. As both scientists and duck enthusiasts placed these boxes in wood duck habitat, the bottleneck of nesting location was effectively removed and wood duck numbers significantly increased.

Currently, wood duck population numbers are stable and large, with an estimated 4.6 million individuals in the wild. This duck is a fantastic example of how both protection through policy and a little bit of reproductive assistance can go a long way in the recovery of a species.

Social Life
Male wood ducks will pair with a single female for a breeding season, but usually pair with a new female the next season. They are fairly social birds, and often roost and migrate in pairs or small flocks.

Nesting females have a fascinating behavior called conspecific brood parasitism. This means that sometimes a female will seek out her own nesting hollow or nest box and lay her eggs there, but sometimes will find other females’ nests to lay her eggs in. Scientists are still unsure of what exactly prompts females to make this decision—there is certainly a benefit to continuing your genetic lineage without needing to rear any chicks yourself, but the more females that decide to forgo having their own nest, the less nests are available for parasitism and the worse of a decision that becomes. This leads to complex nesting behavior—it may be advantageous for females to be especially secretive when entering and leaving their nests, not just because of predation risk but to prevent other females from discovering the nest location and laying their eggs there. “Dump nests” of more than 50 unincubated eggs have been found, perhaps these are formed when too many females learn about a nesting location and the original eggs become crushed under the weight of new eggs, leading to abandonment of the nest.

Wood ducklings are highly precocial, meaning they are capable of moving around the world and feeding themselves soon after birth. These ducklings typically leave the nest within the first day after they are born. Because they nest up in tree hollows or nest boxes, they must make a leap of faith down to the forest floor together, before following their mother to the nearest waterway.

Habitat and Range
Wood ducks migrate up and down all 4 of the major flyways in North America: the Pacific Flyway, Central Flyway, Mississippi Flyway, and Atlantic Flyway. They move between Canada and the northern US, to Mexico, Cuba, and the southern US.

Wood ducks spend their time in freshwater pools, lakes, and waterways, preferably with dense surrounding woodland vegetation.

Diet
Wood ducks are omnivores, eating nuts, namely acorns, seeds, and various aquatic plants, as well as a variety of invertebrates.

Predators
Wood ducks and their ducklings are often preyed upon by owls, minks, raccoons, foxes, alligators, and snakes. Ducklings have even more predators, and due to their highly precocial nature, they are extremely vulnerable for the first few months of their life.

Reproduction
Sexual Maturity: ~1 year
Nesting Season: ~February – June
Incubation: ~1 month
Clutch Size: highly variable due to conspecific nest parasitism, but typically ~10 – 20 eggs.

adult male wood duck portrait

Adult male wood duck by Mark Pressler

adult female wood duck

Adult female wood duck by Mark Pressler