The American bittern is a well-camouflaged, stealthy, medium-sized heron that lives in wetlands, lakes, and ponds. The neck is thick and the legs are relatively short, for a heron. The bill is long, straight, and looks sharp as a dagger. In Missouri, we usually see it in spring and fall. Listen in spring, at predawn or dusk, for its distinctive gulping calls.
Adult American bitterns are heavily streaked with brown from head to tail, including bold streaking on the neck. There is a black streak on both sides of the neck, though the black streak can sometimes be hard to see. In flight, an American bittern can be told best by the contrasting chocolate brown primaries (primary flight feathers on the outer part of the wings) and lighter brown inner halves of the wings.
The distinctive pumping or gulping, rhythmic song of the males sounds something like the voice of a traditional Yoruba “talking” drum of West Africa: “Boip! Boip! Boip! . . . BOI-boom, BOI-boom, BOI-boom . . .” Others have described it as “Unk! A-lunk, A-lunk, A-lunk.” Listen for it in spring, in the predawn or dusk.
Similar species: The least bittern, about the size of a pigeon, is less than half the size of the American bittern, which is larger than a crow or green heron though smaller than an average goose. Rails are also found in marshy areas, but they, too, are smaller; also, their necks are short and lack the bold streaking of the American bittern.
In flight, American bitterns can be separated from immature night-herons this way: On American bitterns, the chocolate brown color of the outer half of the wing contrasts with the lighter brown of the inner half; on night-herons, the upper wings appear as solid dark brown.
Length: 28 inches (tip of bill to tip of tail).
Statewide.
Habitat and Conservation
Uncommon migrant that rests and forages in marshes, wet meadows, and marshy shorelines of lakes and ponds. Extremely rare and local breeder in marshes.
American bitterns are hard to see because they are so well camouflaged against the many cattails, sedges, and other emergent aquatic plants they hide among. They typically hold completely still as they wait for prey to draw within striking distance. When alarmed, they extend their neck and bill straight upward and stand motionless, enhancing their camouflage by swaying slightly with the nearby grasses in the breeze.
American bitterns are most easily observed in wetlands at dawn and dusk during spring migration. Spring is best because the vegetation has not grown tall enough to conceal them. Wetland areas with shallow water and marsh or grassland vegetation are good locations to search for American bitterns.
Food
Like other herons, the American bittern forages around shallow water, stalking prey slowly, then quickly jabbing with its bill. Prey includes a long list of small fish, crayfish, insects including grasshoppers, water bugs, and dragonflies, frogs and other amphibians, small snakes, and other small animals it can capture and swallow.
While stalking prey, this bittern often holds its head and bill level with the water, with just the eyes rotating downward (giving it a rather cross-eyed look). Once it sees prey, it slowly aims the bill downward, then strikes in a lightning-fast move.
Status
Uncommon transient; rare summer (breeding) resident; accidental winter visitor. A Missouri species of conservation concern, listed as endangered in Missouri.
Life Cycle
Present in Missouri from late March through September; numbers are highest during spring migration, from mid-April to mid-May. It sometimes breeds in Missouri, especially in the northern half of the state, but most American bitterns breed in Canada and in the northern half of the Lower 48. The winter range is along the Gulf Coast states, the US southwest, and Mexico.
Female American bitterns build nests amid thick growths of cattails, sedges, and other emergent wetland plants. The nests are raised a few inches above the water line, on platforms constructed of vegetation, or sometimes they are positioned on the ground. A clutch comprises 2–7 eggs, which are incubated for 24–28 days. The young remain in the nest for 1 or 2 weeks. Females build and tend the nest and nestlings without assistance from the male.
Human Connections
Birding is a kind of sport, and trying to see some of the hard-to-see species is a real challenge! Here is a hint for seeing American bitterns: in springtime, look for them at big wetlands, such as Eagle Bluffs, Schell-Osage, Fountain-Grove, Ted Shanks, and Marais Temps Clair conservation areas and the Mingo, Loess Bluffs, Swan Lake, and Mark Twain national wildlife refuges.
The unusual voice of the American bittern inspired many of the colorful nicknames that have been used for this bird: thunder pumper, mire drum, butterbump, and bog bull. Many naturalists have tried to describe the song. In the early 1900s, ornithologist Edward Howe Forbush wrote, “While producing the sound the bird looks as if trying to rid itself of some distress of the stomach and the resulting melody sounds much like the sucking of an old-fashioned wooden pump when some one tries to raise the water. The bird suddenly lowers and raises its head and throws it far forward with a convulsive jerk, at the same time opening and shutting the bill with a click. This is accompanied by a sound which resembles a hiccough.” He translated the ensuing pumping noises as “plunk-a-lunk” but admitted that others had translated it as “plum pudd’n.”
Forbush also described the song’s odd acoustic properties, saying that the volume seems no different whether the bird is near or far, and that it’s difficult to determine where the call is coming from. At large distances, however, the only sound that can be heard are the well-separated thumps: “a single note closely resembling the driving of a stake,” which explains the bird's nickname “stake driver.”
Ecosystem Connections
American bitterns are an integral part of a wetlands community. As predators, they help control the populations of the many animals they eat. But though the adults are well-camouflaged, capable of flight, and possess imposing weaponry in the form of their daggerlike bills, the young are quite helpless. A wide array of predators can access the nests, so close to the ground, and eat the eggs or nestlings. Watersnakes, muskrats, minks, birds of prey, and other predators are ready to capture the young. For this reason, the mother bittern is especially protective of her nest and young.
Like other migratory animals, American bitterns play a role in all the regions they pass through in their yearly journeys.
American bittern populations appear to be declining, but overall they remain fairly common. This species is difficult to study, since individuals are so hard to observe. As with other species that rely on wetland habitats, their numbers decline when wetlands are destroyed or degraded. Pesticides and other pollutants are some of the other threats.
About 350 species of birds are likely to be seen in Missouri, though nearly 400 have been recorded within our borders. Most people know a bird when they see one — it has feathers, wings, and a bill. Birds are warm-blooded, and most species can fly. Many migrate hundreds or thousands of miles. Birds lay hard-shelled eggs (often in a nest), and the parents care for the young. Many communicate with songs and calls.