A True Tree Duck
by Juanita Baker, Ph.D., Birds Need Plants Photo Contest
No other duck-like bird has these long white feathers on its wing. So if you see these ducks flying by with that marker, you know you’ve just seen a Black-bellied Whistling Duck! In May, Ellie Van Os photographed this one on Blue Cypress Lake, perhaps leaving the hollow of a bald cypress tree where it likely had a nest.
Most bird species are quickly identified by a few key markers differentiating them from all other species. Whistling ducks are in their own unique subfamily, Dendrocygninae, within the waterbirds family Anatidae (with Ducks, Swans, Geese subfamilies). Unlike diving and dabbling “true” ducks, their genders are indistinguishably patterned. They ‘whistle’ as they fly by, have long necks and long legs. They use their long necks during courtship to stretch forward, horizontally, dipping under the water, and rapidly throwing their necks back to toss water over their backs! That must be a grand gesture to attract their mate.
So how does this duck need and use plants? In addition to their largely vegetarian diet, they usually use tree hollows for nesting, with plant material for building and lining those nests. They have evolved special web-scales to better grasp branches while perching. Generally gregarious, they fly in large flocks after dark and before dawn to feeding sites and have bills adaptable for grazing. They forage in fields for grains like rice, sorghum, corn, wheat, and for grasses near water bodies, although they also eat about 8% animals—mollusks, snails, and insects. During breeding season, when more energy enriching foods are needed, they will forage in the daytime also. Look for these unusual ducks during daylight on the edges of freshwater vegetated areas in shallow waters no deeper than the length of their long legs.