Be Your Own Birder

Bird of the Week: Mottled Duck

My history with this week’s featured bird is mottled indeed, and the mottled duck can be confusing for many birders – until you learn the little clues that help you easily separate this dabbling duck from similar species. You’ll be amazed at how easy it can be, once you know what to look for!

Mottled Duck

Mottled Duck – Photo by Andy Reago & Chrissy McClarren

Name: Mottled Duck, Mottled Mallard
Scientific Name: Anas fulvigula
Scientific Family: Anatidae (Ducks, Geese and Swans)

Habitat: Mottled ducks prefer freshwater or slightly brackish marshes, shallow lagoons, wetlands, retention areas and similar habitats, including those that may only be flooded seasonally, such as during storm seasons. They are often found in ditches or other water overflow areas, and may also be seen in urban or suburban areas where appropriate aquatic habitats exist.

Range: These ducks are year-round residents in the southern United States from South Carolina to southeastern Arizona, though the most common populations are only in the southernmost areas of the included states, such as along the Gulf Coast and Rio Grande. They are also found in central-western Mexico, as well as along the Mexican Gulf Coast.

The mottled duck is very aptly named for its mottled plumage in shades of buff, brown, gray and black. The head and neck are paler, plainer buff, and a dark eye line contrasts with the plain face. The bill is primarily yellow but may have a very slight smudgy appearance, and the speculum in the wing is purple-blue with a black border. The legs and feet are bright orange. Males and females look alike, though the male’s bill is brighter than the females.

As dabbling ducks, these birds exhibit all the classic behaviors we expect from mallards – gathering in groups, mingling with other ducks and tipping up to feed in the water or waddling on land as they graze. They can be wary or tame depending on their exposure to humans, and when they take flight it is with the burst of energy from the water’s surface with rapid wing beats and a direct flight path.

Because of their similar appearance and behaviors, at first glance (or even second and third), the mottled duck is easily confused for a female mallard. The key is to know what to look for to confidently separate these birds…

  • Much paler head and neck, even showing a collar-like contrast to the body (female mallards have distinctly darker heads, especially the crown and nape)
  • Prominent dark spot at the base of the bill where the mandibles join (this is lacking on mallards, though be aware of shadows or viewing angle to be confident)
  • Only very thin white borders on the outer edge of the speculum (mallards have broader white borders that show very well)
  • Significantly darker tails that show the same mottling colors as on the body (female mallards have paler tails with more white or cream coloration)

Range used to be a good clue to distinguish the mottled duck as well, but unfortunately, domestic mallards are introduced in many areas where mottled ducks thrive, and are slowly edging out these birds as they compete for food and nesting sites. Furthermore, mottled ducks and mallards easily hybridize, further blurring the lines between species and making it difficult to definitively identify some birds in the field. That interbreeding can even threaten mottled ducks further as pure populations decline and these ducks edge ever closer to vulnerable and endangered status.

I’m fortunate that mottled ducks are common in my area – so common, in fact, that it’s taken me months to work out the key field marks to be positive of my own identification. I was continually seeing these birds at the most inopportune times – at the post office (a drainage pond that filled after Hurricane Irma), at the bank (a year-round retention pond with marshy edges) and at the library (a large pond and park-like area home to wild and domestic waterfowl at different times). It was finally at the library where I’d remembered to bring my birding gear and set about identifying these ducks in a more efficient way, and within moments I’d spotted each field mark necessary to know I’d seen a mottled duck. For a few hours, I was even excited that the bird could be a lifer – until I checked my official records and discovered that I’d done all this work five years earlier and added the species to my list then. But, now I KNOW those marks much better, and won’t be confused by this bird’s sneaky mallard-like camouflage again!

Leave a Reply

Your email address will not be published.