State of the Species: Mottled Duck (Anas fulvigula)
Written by: Kaytlin Cowser, Guest Contributor
As the morning sun shines across the land, the fog clears over the wetland prairie. In the distance you hear a faint sound, you grab your binoculars. Quickly trying to identify the small flock of ducks in the distance, you realize you have spotted the mottled duck.
These non-migratory birds can be found living along the Gulf Coast all year round. They inhabit freshwater-brackish marshes, wet prairies, rice fields, and shallow ponds with abundant vegetation. They are the most southern dabbling duck seen in the southern marshes, with two populations in North America. The larger population resides along the Gulf of Mexico spanning from Alabama to Veracruz, Mexico with the greatest number being found in the Texas Chenier Plain (Sabine Pass to Galveston Bay) and moderate numbers extending to the Texas mid coast (Corpus Christi). The second population is smaller and resides in the Florida peninsula. The total current population observed by Partners in Flight is estimated to be 460,000.
The mottled duck is a medium-sized brown/buff duck, with a short tail and a short neck. The bill on this duck is moderately long in size and brightly colored. They are extremely similar in appearance and closely related to the mallard, Mexican duck, and the American black duck. The unique feature used for identifying the mottled duck is its distinctive black spot at the gape (the opening of their bill). Distinguishing between the male and female mottled ducks can be difficult due to their plumage, which is very similar in appearance. When compared to females, the male’s head and neck are slightly lighter than its body. The easiest way to tell a male and a female apart is by the bill color. A male’s bill will be a bright yellow to olive color whereas a female’s bill will be an orange to brown color with dark spots on the underside.
Mottled ducks are a dabbling duck that primarily feed on the surface or slightly submerged vegetation. They retrieve food by tipping their tail skyward and dunking their head down to grab food. The mottled duck doesn’t usually dive underwater unless being pursued by a predator. Ducks are omnivores that need an abundance of emergent vegetation such as grasses, stems, roots, and grass seeds. Small fish and invertebrate prey like snails, crayfish, beetles, dragonflies larva, midges, and even zooplankton are other favorites of the mottled duck. Did you know that females consume mostly invertebrates during breeding, as do the ducklings?
The mottled duck begins looking for a new mate every season, usually before most other ducks. This pairing process begins early and extends to November, when most pairs have been made. They display a courtship of movements and sounds directed at a potential mate to make a bond, only lasting a few minutes. Once mated, the mottled ducks fly low over their habitat looking for a suitable environment for their nest. The female has the deciding vote on the exact location, usually under a shrub or tall grasses near freshwater. The nest is then built in a bowl shape depression in the grass lined with grass litter, shredded grass, and down from the female’s breast. Breeding begins in January with a peak occurring between March and May, extending until the end of July. The bonded pair usually separates with the male leaving the nest before the babies have hatched. The hatchlings are covered in down when born, allowing them to leave the nest to search for food. They can be been seen in small flocks during the molting process. Once they have grown their adult plumage, they fly to find a suitable environment and begin their own mating process. Sizable flocks can be seen during the autumn and winter months where an abundant food source is present.
Mottled duck populations have seen a 78% decline from 1966-2015 according to the North American Breeding Bird Survey - reaching one of the highest levels of concern with Partners in Flight on their red watch list. The Florida population is of particular concern as domesticated mallard ducks have been released into the wild. These domesticated mallard ducks are sterile but are closely related to the mottled duck. Hybridization from crossbreeding is causing the mottled duck population to have offspring with mallard duck genes. The mallard-mottled duck (known in Florida as the muddled duck) poses a significant threat to Florida’s true mottled duck population. The mallard gene is easily identified by looking at the mottled duck’s tail. If the tail is all brown and buff, the duck is a pure mottled duck. If the tail has white feathers present, it is a mallard hybrid. These observations enable observers to make a more accurate account of the population of pure mottled ducks.
Another important concern for the mottled duck is the loss of habitat due to urban sprawl, as well as coastal marshland degradation. The spread of invasive species like the Chinese tallow is also invading mottled duck nesting habitat. This could potentially lead to abandonment of the area and loss of habitat. Conservation projects and invasive species removal performed by the Coastal Prairie Conservancy and other partners helps protect habitats.
With the loss of habitat and drastic decline in population, the mottled duck has gained the attention of conservationist and wildlife managers along the Gulf Coast. Nesting and brood-rearing models have been made to aid in targeting areas for conservation and management, as well as identifying and prioritizing areas for grassland and wetland establishment. These potential habitats need abundant food sources and shallow water depth with proper native vegetation and density. By obtaining the proper parameters, conservation efforts like those at the Coastal Prairie Conservancy can help preserve and restore sustainable habitat for the mottled duck in southeast Texas.
With most lands in Texas being privately owned, conservation measures from private landowners are immensely helpful. The Coastal Prairie Conservancy works with many landowners to preserve the Texas coastal prairie and the critical wildlife habitat that is found here. Mottled ducks are just one of the many species that benefits from grassland and wetland restoration and the preservation of wide-open spaces. Learn more about the Coastal Prairie Conservancy’s work here. Thank you for supporting this important work!
What can volunteers do? Helping with wetland restoration is huge! By participating in activities such as seed collecting, Stewardship Saturdays, the Great Grow Out, and the annual Putting Down Roots event, volunteers help ensure that the grassland and wetland habitats used by mottled ducks on the coastal prairie stay healthy and resilient.