Denizen of the Reeds: The Secretive American Bittern

We have been experiencing a delightfully rainy winter this year in California's Great Central Valley.  The hills and grasslands are green, wildflowers are blooming in abundance, and the valley's rivers and wetlands are full to the brim.  While many of our overwintering birds have departed, the wilds and wetlands are still a flurry of spring activity as resident birds begin nesting and migrants return.

On our recent trip to Merced National Wildlife Refuge, we came across one particularly fascinating bird of the wetlands: the American Bittern (Botaurus lentiginosus).

Though not particularly rare, American Bitterns are secretive birds that generally prefer to stay hidden in thickets of reeds.  During the spring mating season, one may hear their deep resonating "plum-plump" or "pump-er-lunk" call carrying great distances across the marshes.  It is such a distinctive call, there's no mistaking it.  And yet, hopeful birders can search and search for a glimpse of the elusive bird, only to be defeated time and time again as it remains hidden in dense stands of tules.  (Trust me, I speak from experience!)

Related to herons and egrets, American Bitterns stand about 2.5 feet tall, with 3-foot wingspans.  They are not small birds!  But they are cryptically colored, with brown vertical stripes down the length of the neck.  Using this coloring to their full advantage, American Bitterns have developed a strategic habit to avoid detection.  With bill pointed to the sky, the bittern elongates its neck and stands perfectly still, its stripes allowing it to blend seamlessly (so it believes) into a forest of reeds.  On breezy days, it may even sway slightly to mimic the motion of the reeds!

American Bitterns are found in shallow freshwater marshes across the northern part of the United States and southern half of Canada.  As temperatures drop below freezing, they migrate south to the Gulf Coast, southeastern United States and Mexico.  In places where winters are mild, such as California's Central Valley and coast, they stay year-round.

American Bitterns tend to stick close to the edges of wetlands and under the cover of reeds; rarely are they seen in the open.  In addition to being secretive, they are also solitary birds, coming together only briefly to mate or settle a territorial dispute.

Opportunistic stealth hunters, American Bitterns will prey on a wide variety of animals that happen across their path.  They tend to hunt most frequently at dawn and dusk, when light levels are lower.  Waiting patiently along a shoreline or at the edge of vegetation, the bittern moves very slowly, carefully, stealthily as it aims its bill toward the intended prey, until with a sudden flash it darts its head out to strike its prey.  Prey items are swallowed whole (head first) and indigestible parts, like bones, are regurgitated later as pellets (like owls and other birds of prey).

Animals that might find themselves falling prey to the quick strike of an unseen American Bittern are fish (including eels and catfish!), crabs, amphibians (frogs and salamanders), water snakes, small mammals (like voles) and large aquatic insects like water striders and water bugs.

Creeping slowly away, the American Bittern disappears into its reedy sanctuary.

As reedy marshes across North American are drained and habitat dwindles, protected and managed wetlands, like those found in our National Wildlife Refuge system, become increasingly important for the continued success of species like the American Bittern.

And there's no time quite like spring to get outside to explore and appreciate your local wetlands.  You never know what you may find stealthily stalking through the reeds!