Two Species, Same Habitat, Different Times

     While walking along a tumbling stream in woodland one recent winter afternoon, I noticed a slight movement near the water's edge.  Looking at that spot with binoculars, I quickly noticed a winter wren hopping about among a tangle of tree roots in the stream bank.  Winter wrens, like all their feathered clan, are brown and smaller than sparrows, making them camouflaged on woodland floors and along stream banks.  They are impossible to see until they move. 
     While watching the wren briefly, I remembered seeing a pair of Louisiana waterthrushes nesting along that same section of stream this past summer.  Here in Lancaster County, Pennsylvania, as elsewhere in eastern North America, winter wrens and Louisiana waterthrushes use the same
 charming, musical streams in woodlands, the wren in winter to forage for invertebrate food kept active by the running water and sheltering tree roots, and the waterthrushes in summer to raise young.  Both kinds of birds use those same beautiful habitats, but not at the same time for the most part.  However, they might overlap each other early in April when the waterthrushes have returned here to nest, but the wrens hadn't left yet to push farther north to breed. 
     Winter wrens and waterthrushes aren't related and don't look alike, but both are insectivorous, finding food under carpets of fallen leaves on forest floors, in brush piles, under fallen logs, in crevices between boulders, among exposed and tangled tree roots in stream banks and along the water's edge.  Males of each species have loud voices so females of their respective kinds can hear them amid the rush of water and find them for mating.
     Winter wrens breed in spruce/fir forests of the northeastern United States and eastern Canada.  And they winter along streams in deciduous woods in much of the Lower 48.  Each wren is a stub-tailed, mouse of a bird that creeps about on leafy, forest floors and stream banks in search of invertebrate food.  Those sheltered places harbor tiny critters the wrens seek, particularly after a snow fall when much invertebrate food is buried under snow.  And the running water on stream edges doesn't freeze, keeping some invertebrates active and available through winter, the reason why winter wrens are in that niche at that time.                
     Louisiana waterthrushes winter in the forests of Central America, but nest in wooded stream valleys in the eastern half of the United States.  They tuck their cradles of dead leaves and grass in niches under tree roots in stream banks in the woods where they are protected from most predators, except mink and black rat snakes. 
     Playing the role of sandpipers where that family of birds would not be, waterthrushes forage mostly for invertebrates in the stony shallows of the streams where they build their nurseries.  As they walk along the water's edges and among the pebbles, waterthrushes bob and dance like debris bouncing along in the flowing water, which is a form of camouflage, confusing would-be predators.
Birds of this species are also difficult to notice until they move, or fly stiff-winged and swiftly across the waterway.
     These species of birds share a similar habitat, but usually not at the same time.  And they are both hard to spot.  Often they are heard before seen.  But they are interesting little creatures when along streams in the woods, making that habitat more interesting.