190 
TENTH REPORT. 
27. Brown Thrasher. Common summer resident generally around brush 
piles; breeds. 
28. Tufted Titmouse. Accidental fall visitant. 
29. Wilson’s Thrush. Rare migrant. 
30. Hermit Thrush. Rare migrant. 
31. Robin. Common throughout the summer; nests along fences. 
32. Blue Bird. Common migant; found along the fences. 
GENERAL SUMMARY. 
In order to understand the relation between the physical changes, the 
vegetation, and the bird life of the region, it is necessary to summarize the 
present conditions, the plant and bird life, and the changes taking place in 
connection with the processes which are causing them. 
Swamp. ( Sta . I.) The swamp consists of an open bayou and a stretch 
of flood-plain thus including a sheet of open water, mud flats, a marsh over- 
grown with reeds, flags, and cattails, and an area of swampy ground covered 
with shrubby willows. 
The birds found here are characteristic of swamps in general, the Coot 
frequenting the open bays, the Sandpiper the mud flats, while the Marsh 
Wrens live exclusively in the flags and sedges. The Red-winged Black 
birds nest in the cattails, and Catbirds together with the Yellow Warbler 
are found most abundant in the shrubby willows. 
Deposition, due both to the depositing of material by the river and the 
accumulation of material from decaying plants, is the dominant process in 
this habitat. As the submerged plants die they drop to the bottom and 
soon form a layer of considerable thickness. The river, especially during 
the spring floods, adds considerable quantities of earthy material and in a 
short time the water becomes shallow enough for the deep water sedges. 
Once these have a good foothold, the land rises rapidly as the roots and 
stems of the sedge help to catch and hold the material from being washed away. 
As the water becomes more shallow the other sedges together with the flags 
and cattails appear. The decay of these plants raises the land still faster 
and in a comparatively short time clumps of shrubby willows appear. Depo- 
sition then extends the area of each plant further out into the river, but the 
same force is building up the ground back of them thus shortening the area 
on that side. With this progression in the plant forms, there is one in the 
bird life complimentary to it, so that as the habitats advance those birds 
which find in each the conditions best adapted to themselves also advance, 
but at the same time they must withdraw from the unfavorable conditions 
which are springing up behind them. 
Arboreal Willows. (Sta. II). This habitat consists of a strip of till covered 
with humus and overgrown with large willow trees and very little under- 
brush. There is little change taking place here, the soil is washed out by the 
rains and some of it redeposited at different points, and the river during 
flood times also deposits quantities of material especially along the outer 
edge. It is evident that the processes of erosion and deposition are about 
equal. The vegetation is therefore mainly dependent on the topography. 
The Mourning Dove, Baltimore Oriole, and Wood Pewee, characteristic 
birds of the large willows bordering streams, are principally found here. The 
habitat of these birds at present is only increasing to a very slight extent 
the arboreal willows getting a foothold a little further out in the marsh 
than formerly. 
