NESTING ALONG STREAMBANKS IN WOODS

      Four kinds of small birds, including Louisiana waterthrushes, rough-winged swallows, Acadian flycatchers and eastern phoebes, have characteristics in common because of the nesting habitat they share along streams in eastern North America woodlands.  That habitat molded them to be as they are. 

    These small birds are brownish or grayish, which camouflages them along streambanks in shaded woods.  Two kinds utter loud songs to be heard above the musically-tumbling stream.  They all consume the abundant invertebrates that live along clear, flowing waterways, and feed those critters to their young birds in their nests.  But they catch those critters in different ways, which reduces competition for food among  them, and helps make them be distinct species. 

     Waterthrushes seek invertebrates under stones along stream shallows and their gravelly edges.  They even flip some stones over to look for invertebrates that were under them.  

     Each waterthrush bounces its whole body while walking along waters' edges in search of invertebrate food.  I wondered why they do that.  Then I saw bits of bark and leaves bouncing along in a stream current with the same rhythm as the birds' bobbing  That constant dipping by the waterthrushes is a form of camouflage to blend into the background of bobbing plant material in a flowing waterway to avoid the attentions of predators. 

     Male waterthrushes sing loud, bubbling songs to establish nesting areas, chase away other males and attract mates for raising offspring.  Waterthrushes place dead leaves in shallow crevices in streambanks to create nurseries, often behind concealing tree roots.  The dead leaves camouflage and hide the eggs and young in their soil cradles until those birds are ready to fly.   

     Rough-winged swallows hatch young in soil tunnels they dig into streambanks.  However, some pairs use abandoned kingfisher burrows to raise babies in relative safety.  And still other pairs of rough-wings hatch offspring in pipes and drains that extend over waterways under bridges.  Using those human-made structures has helped to increase rough-wings' numbers.  

     Rough-winged swallows are entertaining to watch swirling and sweeping low over waterways after the flying insects they catch, ingest and feed to their young.  Swallows don't compete with other birds for insect food.  

     Acadian flycatchers place their open-cup nurseries of rootlets and grass in crotches of trees, usually beeches that lean over waterways.  Acadians perch on twigs and watch for passing insects.  When insects are spotted, each Acadian flips out, catches the victim in its beak and flutters back to a twig to eat its prey, and watch for more.   

     Male Acadians abruptly and loudly sing "spit-chee" to establish nesting territories, repel other males of their kind and attract mates for raising youngsters.  

     Eastern phoebes are another kind of flycatcher nesting in woods of eastern United States.  They traditionally build soil and moss cradles on boulders under overhanging boulders near streams in woodlands.  But some pairs of phoebes create nurseries on support beams of porches, pavilions and small bridges in woodlands.  They catch insects the way their relatives, Acadian flycatchers, do.  And phoebes utter cheerful "fee-bee, fee-bee" songs through the day, every day, while building nests, incubating eggs and feeding young.  They are good neighbors to have around homes in the woods. 

     These types of charming, little birds are adapted to nesting along streams in the woods of the Eastern United States.  They are interesting little critters in summer, but in September they migrate to Central and South America, where they can catch flying insects during the northern winter.  But next spring, they will be back along streams in American woodlands, ready to consume invertebrates and raise young.