Creature Feature – Ol’ Thunder Pumper

Late spring into early summer offers an abundance of avian arias, as recently arrived migratory birds seek mates and establish territories. Speaking of bird sounds, some are unforgettable, like a loon’s haunting call or the ethereal flute-like song of the wood thrush; but there’s none so weirdly wonderful as the call of the American Bittern, or “thunder-pumper!”  

The American Bittern is a reclusive, medium-sized heron found in the dense vegetation around lakes, ponds, and wetland habitats. While not uncommon by any means, it is rarely seen, as its cryptic plumage and highly secretive nature allow it to “disappear” in the thick reeds and cattails – but its one-of-a-kind voice betrays its presence.

During breeding season, the male bittern produces a guttural territorial call: “pump-er-lunk, pumper-lunk, pumper-lunk…!” The call has an unmistakable liquid quality to it, like that of a water pump or a glugging water jug. It’s mind boggling to ponder how this mechanical-sounding vocalization comes from a bird. To produce the bizarre sound, the bittern must inflate his esophagus by drawing in several large gulps of air before using the stored air to broadcast his territory and solicit a mate. 

The low-frequency call carries farther through dense vegetation than higher-pitched sounds; so as strange as it may sound to us, the call of the American Bittern is perfectly suited to its specific habitat. Like I said, it’s “weirdly wonderful!”

Article & photo by Margie Manthey