Nesting Along Woodland Streams

     Several kinds of small birds nest in individual pairs along woodland streams in Lancaster County, Pennsylvania, as elsewhere in much of North America.  They are all migrants, having come north from farther south where they spent the northern winter.  Each type of bird has its own nesting niche, which reduces competition for breeding space and invertebrate food with its feathered neighbors.
     All these nesting species, except one, are camouflaged in their summer niches, making them difficult to see until they move, which protects them from predators.  Often these little birds, tucked away in foliage, are heard before spotted.  Use a field guide to eastern North American birds to identify the following woodland species.      
     Louisiana waterthrushes and rough-winged swallows nest in woodland stream banks.    Mud-brown on top, waterthrushes select notches in the soil of the banks, usually behind exposed tree roots for added concealment.  They line their cradles with pieces of dead and fallen leaves and rootlets.  Parent waterthrushes walk and bob in shallows along the musically flowing water to catch invertebrates from under stones to feed themselves and their young in their nurseries.  Males of this species sing loud songs so potential mates can hear them over the tumbling waterways.
     The plain, gray-brown rough-winged swallows dig burrows in the soil of stream banks, or use abandoned kingfisher tunnels, to hatch young.  The swallows snare flying insects in mid-air over the water and feed many of them to their offspring.  Some pairs of rough-wings raise young in drainage holes under bridges, which to them, I suppose, is like deserted kingfisher holes in stream banks.     
     Acadian flycatchers build cup-sized nests of grass, rootlets and spider webs that sag below twigs of American beech tree limbs, many of which extend over woodland streams.  Like all flycatchers, the gray, little Acadians perch on twigs and flip out to catch flying insects that they consume on the same or another perch.  Males' songs are an explosive "peet-sa".
     Deep-yellow all over and striking, prothonotory warblers nest in abandoned woodpecker holes and other tree cavities along woodland waterways.  They ingest invertebrates they find among tree foliage in the woods.
     The plain-gray eastern phoebes are another kind of flycatcher that nest in local woods and catch flying insects over the water and in the woods, much the way Acadian flycatchers do.  Phoebes traditionally make nurseries of mud and moss on rock ledges under over-hanging boulders near little waterways in the woods.  Today, however, they also hatch young on support beams under small bridges and porch roofs near water in woodlands.  They seem to have little fear of people.  Males sing a simple, repetitive "fee-bee, fee-bee", which is companionable to people living in woodland homes where phoebes raise offspring.
     Veeries, which are a kind of brown-backed, spot-breasted woodland thrush, nest on the dead-leaf carpet of forest floors on wooded bottomlands near little waterways.  Males sing spiraling, descending, flute-like songs that are unique, and inspiring to hear.  All species of woodland thrushes run and stop, run and stop across dead-leaf carpeted, woodland floors, as their relatives, the robins, do on lawns, to catch and ingest a variety of invertebrates.
     Worm-eating warblers are olive-brown, with beige and dark stripes from beaks to necks.  These little birds sing dry trills and nest in the leaf litter of wooded slopes a short distance above woodland streams.  Like veeries, they hunt invertebrates on forest floors and create nests in the dead-leaf rugs of forest slopes.  
     By late summer, into autumn, these birds migrate south again to avoid the hardships of northern winters.  But they are intriguing little birds when spotted, or heard, along woodland streams.