by Denny Olson
American Bitterns are in the heron family, all no strangers to swamps. They are often described as “secretive” or “elusive”, but those conclusions are drawn by a high-and-dry species (us), which does not spend much time in the marshes and swamps. Another reason for that perception is their amazing cryptic coloration (buff and brown vertical stripes in identical shades to cattails, rushes and sedges), and cryptic behavior. When they stick their beaks into the air and their body goes vertical – and they freeze – a 30-inch tall bird can literally disappear. But that camouflage skill is completely dependent on where they normally live.
I was once in a marsh for more vegetative reasons, trying to find an uncommon orchid, when a Bittern hopped onto the gravel road causeway through that marsh. It was time to reload gravel into its gizzard. A good-sized pickup truck barreled down the road far too fast for conditions. The driver spotted the Bittern, slammed on the brakes, and stopped five feet away in a cloud of dust. The Bittern stuck its beak into the air and froze. There was a slight breeze, and the bird, being the perceptive type, even swayed slightly like blades of cattail leaves. The truck driver was befuddled at first, but then started to laugh. “Dude, wrong background.” Instincts don’t always operate in the best interests of Bitterns.
Another adaptation tuned to that instinctive behavior is the placement of bittern eyes. They are located down far enough on their skulls to be able to look 360 degrees when in their “you can’t see me” posture. Even though their beak is vertical with throat pointed our way, they can look directly at us. The downward-facing eyes also assist in finding their insect, amphibian, crayfish, small mammal and fish prey.
But come springtime, male Bitterns are anything but elusive. They park in their chosen territories, inflate their esophagus and thrash their necks violently upward, emitting a loud, eerie, low pitched, ventriloquistic “dunk — a-doo”. It’s a serious message to other males, and trespassers are chased and pecked in a spiraling ascending flight with a dagger-like bill. Ground encounters between males are done in a low crouch, with normally covered white plumes showing prominently at the crook of their wings.
Mating happens mostly in April, and there the pair bond dissolves and the genders become solitary again. Somewhat ironically, even though they have little to do with each other, females often build their nests close to a territorial male, whose antics probably distract predators away from the nest. The nest is a platform built of reeds and grasses over shallow water. Eggs hatch mostly in May, and young stay in the nest until fledging in July.
American Bittern populations have declined 43% since 1966, some of the declines due to human disturbance or contamination. But, the fate of such an odd and iconic bird is inextricably linked to the fate of wetlands, and of course, habitat loss is the main culprit in the decline. “Draining the swamp” might be a popular metaphor in politics, but its political insensitivity is indicative of a real ignorance. It behooves us humans, if we want a healthy world, to leave the swamp alone, thank you very much…