They continue to pass, traveling by night and feeding by day, till after the middle of May, when they cease.  In September, with numbers greatly increased, they are on their way back.  I am first advised of their return by hearing their calls at night as they fly over the city.  On certain nights the sound becomes quite noticeable.  I have awakened in the middle of the night, and, through the open window, as I lay in bed, heard their faint notes.  The warblers begin to return about the same time, and are clearly distinguished by their timid yeaps.  On dark, cloudy nights the birds seem confused by the lights of the city, and apparently wander about above it.

In the spring the same curious incident is repeated, though but few voices can be identified.  I make out the snowbird, the bobolink, the warblers, and on two nights during the early part of May I heard very clearly the call of the sandpipers.

Instead of the bobolink, one encounters here, in the June meadows, the black-throated bunting, a bird very closely related to the sparrows and a very persistent if not a very musical songster.  He perches upon the fences and upon the trees by the roadside, and, spreading his tail, gives forth his harsh strain, which may be roughly worded thus:  fscp fscp, fee fee fee.  Like all sounds associated with early summer, it soon has a charm to the ear quite independent of its intrinsic merits.

Outside of the city limits, the great point of interest to the rambler and lover of nature is the Rock Creek region.  Rock Creek is a large, rough, rapid stream, which has its source in the interior of Maryland, and flows in to the Potomac between Washington and Georgetown.  Its course, for five or six miles out of Washington, is marked by great diversity of scenery.  Flowing in a deep valley, which now and then becomes a wild gorge with overhanging rocks and high precipitous headlands, for the most part wooded; here reposing in long, dark reaches, there sweeping and hurrying around a sudden bend or over a rocky bed; receiving at short intervals small runs and spring rivulets, which open up vistas and outlooks to the right and left, of the most charming description,—­Rock Creek has an abundance of all the elements that make up not only pleasing but wild and rugged scenery.  There is perhaps, not another city in the Union that has on its very threshold so much natural beauty and grandeur, such as men seek for in remote forests and mountains.  A few touches of art would convert this whole region, extending from Georgetown to what is known as Crystal Springs, not more than two miles from the present State Department, into a park unequaled by anything in the world.  There are passages between these two points as wild and savage, and apparently as remote from civilization, as anything one meets with in the mountain sources of the Hudson or the Delaware.

One of the tributaries to Rock Creek within this limit is called Piny Branch.  It is a small, noisy brook, flowing through a valley of great natural beauty and picturesqueness, shaded nearly all the way by woods of oak, chestnut, and beech, and abounding in dark recesses and hidden retreats.