Nice views of winter wrens Saturday afternoon along the towpath at Carderock.  Parking at the farthest west lot (upriver), enter the towpath and turn right.  The first wren was in a grass-and-brush hump in the dry canal bed well before you reach the overpass of the entry road.  The second wren was across the canal in a marshy area where the canal widens briefly, just after the overpass.  A little pishing should stir them up, along with the juncos, song sparrows and whitethroats that abound.  Good birding.  David