Fig. 1.—Sketch map of Warren Woods Preserve. The distribution of the various mammal habitats is indicated.
The topography is nearly level, though the area is cut by a number of ravines draining to the Galien River, which flows through the preserve. Along the river and in its bends there are moderate-sized flood-plains.
On the flood-plains a few small buttonbush swamps occur; and along the margins of the river a few freshly formed mud bars have not yet become forested; but most of the flood-plains are covered by heavy forest. The higher ground, except that in the clearing, is covered by heavy beech-maple forest.
Several types of habitats are represented in the clearing: in a few of the cleared ravines a thick growth of sedges and iris occurs; on the higher ground small areas are dominated by rushes, other areas by sedges, while the greater part is covered by grass. In parts of the clearing blackberries and other shrubs have grown up to form thickets, and in many places, especially along the edges of ravines, second-growth trees of oak, maple, or beech grow in the thickets or form small groves.
The mammal habitats found on the preserve may be listed as follows:
| Aquatic habitat | |
| Buttonbush-swamp habitat | |
| Shore habitat | |
| Mud-bar herbage habitat | |
| Flood-plain forest habitat | |
| Beech-maple forest habitat | |
| Aerial habitat |
| Second-growth, forest and scrub habitat | |
| Cleared-ravine sedge habitat | |
| Cleared-upland rush habitat | |
| Cleared-upland sedge habitat | |
| Cleared-upland blue-grass habitat | |
| Cultivated field habitat | |
| Orchard habitat | |
| Edificarian habitat |
It is unfortunate that all of the area in clearing and about half of the forested area on the preserve has been and is being heavily pastured by cattle and horses. The presence of stock has changed the native conditions so much that, so far as interpreting the primitive mammal associations is concerned, little dependence can be placed on studies made in that portion of the preserve. The grass and herbage is extensively eaten off, and many of the shrubs and young trees eaten or badly mutilated. Under the pastured forest little underbrush or herbage remains, and the conditions are very poor for small mammals.
In all the forest, in the unpastured as well as in the pastured part, a number of trees have been cut out in former years, and although no trees are now being cut down, all the trees and branches which fall are being cut up for firewood. This results in there being few logs and little dead brush on the ground, and removes a favorite place for small mammal nests and runways, as well as largely eliminating as mammal food the insects and larvae which are dependent on decaying wood. However, with the exception of the removal of the logs and of a few trees, that part of the forest to the north of the river is still in practically its native condition, and it shows no evidence of ever having been pastured. It is thus a splendid place for the study of the native faunal conditions.