(D) Map of woodrat study area, same as shown in (A), showing first-capture sites for all woodrats live-trapped in 1951. The population was low, but had not yet reached its lowest ebb.
(E) Map of woodrat study area, same as shown in (A), showing first-capture sites for all woodrats live-trapped in 1952, when the population had declined to relatively low numbers and disappeared from much of its former habitat.
(F) Map of the 590-acre Natural History Reservation, showing the area where woodrats were studied.
No. 2. On gently sloping hilltop edge 15 feet from the outcrop and escarpment, built around a forked walnut sapling having both trunks approximately five inches in diameter. The sapling, coming up through the center of the house at a 45° angle, evidently had been bent by the accumulated weight of the debris at an early stage of its growth, many years before. Trees were small in this part of the woods, with a well developed understory thicket of coralberry and sumac. This house approximately one foot high and six feet wide, was constructed mainly of sticks and was similar in composition to No. 1, but appeared considerably older with all the sticks blackened and rotten. In the autumn of 1948 this house was used by woodrats, but probably only as a temporary stopping place, because it was already in disrepair then.
No. 3. At edge of escarpment, 25 feet from No. 2, on a flat boulder approximately six feet long, three feet wide and one foot thick. The decaying and much flattened mass of sticks was mainly on top of the boulder, but also spilled over its edges. Fresh sign was noted at this house in the autumn of 1948, but the house was already in disrepair then, and seemingly it was used only as a stopping place.
No. 4. At the hilltop outcrop where an elm had fallen across it. The decaying log remaining was approximately 12 feet long and 15 inches thick. This log passed diagonally through the house, providing its main support. The house was approximately 39 inches high, its summit extending a little above the level of the top of the outcrop. The house was approximately seven feet wide along the outcrop. This house was somewhat intermediate between the typical dome-shaped stick piles that the rat builds in open situations and the formless accumulations of sticks with which some rats living in deep rock crevices line the entrances. Part of the accumulation was beneath the limestone boulders and outcropping slabs. Approximately half of the material used in the house consisted of sticks and the remainder of pieces of bark and chips of wood, mostly gathered from the fallen elm. This house had shrunken noticeably from decay and settling in the months since it was occupied, in the autumn of 1948. The house was surrounded by a thicket of fragrant sumac, dogwood, and hackberry saplings.
No. 5. At edge of a protruding boulder one foot thick at the hilltop outcrop of the west facing escarpment, and 100 feet back in the woods from the edge of a corn field, in undergrowth of dogwood, wild currant, and coralberry. The house consisted of a pile of rotten twigs, 3 inches deep and 30 inches wide on the upper side of the boulder, and a lining of similar material at the lower edge of the boulder, partly blocking the crevice beneath it. The twigs composing the house were old and rotten. However, a few dry but still green hackberry leaves were stored in the crevice beneath the boulder. In a bare space atop the boulder were several recent woodrat droppings, small and obviously produced by an immature individual, which, perhaps, had recently settled at this old house site.
No. 6. In hilltop woods, 30 feet from a corner adjoining a pasture and a corn field, at the base of an osage orange tree of one foot DBH, and also over a hollow cottonwood log one foot in diameter and three feet from the osage orange tree. Suspended mats of grape and smilax vines, and the thorny, dead, lower branches of the tree provided additional shelter. The house was composed of sticks and twigs, mostly of osage orange, with spines still present; slabs of bark, wood chips, and dry leaves also made up part of it. Materials on the exterior of the house appeared old and weathered, but the house was conical and solid. Seven fresh corn cobs were on the house or near its base, suggesting that corn from the nearby field had figured importantly in the diet of the occupant. A well beaten path led from the base of the house alongside the log, to a large cottonwood tree 15 feet from the house. This evidence that the house was occupied was verified by live-trapping the occupant. Late in 1948, also, the house was occupied by another individual, but seemingly was deserted for a period of months thereafter.
No. 7. On upper part of north slope where a hickory seven inches in diameter had fallen across an old sunken log approximately one foot in diameter. The house, composed mainly of hickory twigs 1/4-inch to 1/2-inch in diameter, mixed with bark, wood chips, and leaves, was partly decayed, with no fresh sign and was in a thicket of greenbrier, saplings of hickory and hackberry, and cut tops of hickories. The top was flattened to less than four inches above the level of the supporting hickory log. There were large cavities in the side of the house. When first discovered in the autumn of 1948, this house was occupied by a subadult female rat, but she moved away permanently, and the house had been deserted for approximately a year when these observations were recorded.
No. 8. In middle of northwest slope, in thick branches of broken top of a black oak. This house had become flattened by decay and settling to form a mound approximately one foot high and five feet in diameter. Only the top protruded through the carpet of dry leaves. Once well protected and partly concealed by the branches and twigs of the oak top, this house was now fully exposed by the disintegration of the top. The house consisted chiefly of oak twigs. In October, 1948, a woodrat was live-trapped at this house, but probably it was a wanderer. The house had then already undergone much deterioration.