American Black Duck, Anas rubripes
The American Black Duck is found locally but in much lower numbers than the similar and well-known Mallard. It’s easy to overlook this large dabbling duck since the two species often live, feed, and interbreed; and they closely resemble the Mallard female. American Black Ducks are found only in eastern North America and they are a year-round resident to our area. Their population is estimated at 400,000 birds compared to Mallards with nearly worldwide distribution and an estimated population of 30 million individuals. We’ll take a closer look at this beautiful bird and learn how to recognize them amongst the masses!
As mentioned above, American Black Ducks closely resemble female Mallards. They appear black from a distance but their artfully colored feathers are mostly dark brown with a fine tan border. Mallard females have lighter brown body feathers with four alternating, oblong rings of medium brown and tan on each feather. American Black Duck males also have a blue-purple speculum (wing bar) without white borders as in the Mallard. Neither sex has white in the tail feathers as seen in both sexes of Mallards. Males can also be distinguished from females by their olive-gray bill; solid yellow on females and their legs and feet are brighter orange to red. Leg and feet color can also be used to determine age with the colors darkening as they age. Their average weight is 2.6 pounds and they have a wingspan of almost 3 feet enabling them to seemingly jump straight up from the water and become immediately airborne.
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These birds are stubborn and loyal to a fault. Migrating individuals return to the same marshes every fall and will starve rather than migrate farther south if those marshes are frozen. This also points to the fact that habitat protection is critical for the survival of these and many other bird species. If a mother is killed or separated from her brood, which can number up to 14 young, another Black Duck with young of her own, will quickly adopt the orphaned ducklings, regardless of their age.
These are dabbling ducks meaning they sit high on the water and feed onshore or in shallow water on vegetation as well as small animals, often seen in the “bottoms up” position. The food choices vary by availability and breeding season with the majority of their diet during winter being snails, aquatic macroinvertebrates such as insect larvae, worms, and small fish. Laying females require a very high percentage of animal-based food matter. During mild weather when green plants are more plentiful, their diet is approximately 80% plant-based. Their ducklings feed almost exclusively on water invertebrates (snails, mayflies, dragonflies, beetles, caddisflies and their larvae) for the first 12 days after hatching. This brings me to the point of humans feeding wild birds, especially waterfowl. Feeding human food to birds is quite unhealthy at best and can be outrightly dangerous to their well-being. They readily eat our stale processed foods but the result can be worse on them than it is to people as it causes malnutrition leading to wing and foot disorders rendering them crippled. The best advice is to enjoy watching but don’t feed the ducks, geese, and swans.
You can learn more about these and other birds by attending Blue Water Audubon meetings held at The Point, 5085 Lakeshore Rd, in Fort Gratiot. Our next meeting will be held on, Thursday, March 5, starting at 6:45 PM and Dr. John Zmiejko will present a program on his recent Mediterranean Birding Trip. You are also encouraged to visit the Blue Water Audubon Society Facebook page for local bird sightings, discussions, and events; be sure to “friend” us!
Tom Dennis is a free-lance writer, passionate birder, zoologist, creation scientist, gardener and naturalist.