12 AVIFAUNA COLUMBIANA. 



low- water mark. During the freshet of February 12, 1881, the water 

 reached at its highest flood the top of the fifth course of stone, about 

 12 feet below the floor of the bridge.* 



This bridge spans the river from cliff to cliff, and is an elegant iron 

 structure, built upon strong buttresses of stone. It derives its name 

 from the fact that the old, original bridge was suspended on chains. 



When the river subsides after a flood, pools of water are left stand- 

 ing here and there over the surface of the low land, around which have 

 grown up several species of swamp willow, together with grasses and 

 shrubby bushes. In these pools are abundance of small fishes, whicli fur- 

 nish food for King-fishers and Green Herons. In this locality many 

 species of birds are found, chief among which may be mentioned the 

 Woodcock (Philohela minor), the Spotted Sandpiper (Tringo'ides macu- 

 larius), the King-fisher (Ceryle alcyon), Green Heron (Butorides vires- 

 cens), and the Maryland Yellow-throat (Geothlypis trichas); while on the 

 clifl's of the Maryland side large colonies of Cliff Swallows (Petrochelidon 

 lunifrons) and Rough- winged Swallows (Stelgidopteryx serripennis) breed. 

 In this locality also the Blue Grosbeak (Guiraca ccerulea) has been found 

 breeding. 



At the head of the Little Falls, about half a mile above Chain Bridge, 

 a dam has been constructed as a feeder to the canal. This creates an 

 extensive lake of smooth water, extending from High Island, at the 

 head of the rapids, up the river for a mile and a half, and has an average 

 width of half a mile. Here are found during the winter season many 

 species of Ducks, and in the summer the beautiful Wood Duck (Aix 

 sponsa) breeds in the neighboring forests. Over its surface during the 

 summer are continually skimming the various species of Swallows. At 

 the upper end of this broad expanse of water are found the beautiful 

 timbered islets appropriately named, by Prof. Lester F. Ward, t Box 

 Elder, Sugar Maple, and Larkspur Islands, where many of the timid 

 wood-birds breed in undisturbed retirement. 



" High Island " lies at the junction of the feeder-dam and the feeder 

 (of the canal), which latter converts it into an island. It is a huge, tow- 

 ering rock, covering several acres. 



Professor Ward eulogizes this locality, botanically, by the remark that 

 the flora of High Island "is by far the most exuberant of all within the 

 knowledge of botanists." We regret that the same cannot be said of 

 fauna. As far as birds are concerned, it is decidedly common place, 

 only a few of the summer residents breeding there, and many localities 

 found more profitable during the spring and fall migration. 



The cliffs on both sides of the river extend from the Little Falls to the 

 Aqueduct Bridge, at Georgetown. On the Maryland side they are soine- 



*This information is kindly furnished by Col. A. F.Rockwell, U. S. A., officer in 

 charge of public buildings and grounds. 



t Gaido to the Flora of the District of Columbia, Bull. 22, U. S. Nat. Mus., 1881, 

 pp. 22, 23. 



