One of our most secretive and best-camouflaged birds, the American bittern, announces itself in the spring, thanks to a booming, low-frequency call—pump-er-lunk; pump-er-lunk—that can carry for up to a kilometre. The strange sound is the reason for the American bittern’s nicknames: “thunder-pumper”; “stake-driver”; and “water-belcher.”
How does a male do it? He inflates his esophagus, then expels the air to create the noise, thrusting his head forward and snapping his beak, repeating the gulp-blow-thrust-snap up to 10 times in a row. It looks weird, but, hey, whatever works for the ladies!
American bitterns stick to woody, reedy marsh areas, where they easily blend in with the vegetation. When a bird is startled, it doesn’t flush or fly away; instead, it will extend its neck straight up and stand, swaying slightly, to mimic a reed. Bitterns forage at dusk and dawn, which makes them even tougher to see. They move very slowly, until they spot something tasty—a frog, a snake, a dragonfly, or a rodent, for example—and jab it with their razor-like beak.
These chunky, medium-sized herons—bigger than a crow, smaller than a goose—nest in shallow water, often in stands of cattails or bulrushes. Unlike some other species, the females do all of the work: they gather nest materials, construct the nursery, then incubate the eggs and raise the chicks with, apparently, no help from their partners.
American bitterns aren’t as graceful-looking as great blue herons, but they do follow the same self-grooming rituals. They have serrated nails on their middle toe claws, which they use for brushing their “powder down” feathers. Sparkling clean! You know, for a bird.