. Controlling field rodents in California. Mammals; Rodents. Fig. 9. Method of the pocket gopher in pushing earth out of a lateral tunnel, by use of the forefeet and head; later the exit will be closed with earth for some distance down the lateral tunnel. Compare fig. 17. and only seldom coming out on the sur- face of the ground. It digs clean-cut round tunnels, about 2 inches in diameter. These are more or less parallel with the surface of the ground, usually at depths of from 6 to 14 inches, but deeper in places. The earth from these (figs. 9 to 11) is pushed out on the surface through short
. Controlling field rodents in California. Mammals; Rodents. Fig. 9. Method of the pocket gopher in pushing earth out of a lateral tunnel, by use of the forefeet and head; later the exit will be closed with earth for some distance down the lateral tunnel. Compare fig. 17. and only seldom coming out on the sur- face of the ground. It digs clean-cut round tunnels, about 2 inches in diameter. These are more or less parallel with the surface of the ground, usually at depths of from 6 to 14 inches, but deeper in places. The earth from these (figs. 9 to 11) is pushed out on the surface through short lateral tunnels made at frequent intervals (or forced into abandoned tunnels). This re- sults in a series of rounded surface mounds which, by their position, usually give a clue to the location of the main tunnel. When putting earth out of a lateral tunnel, the gopher pushes the loads of earth into a more or less crescent-shaped pattern; and when the lateral is closed, a central depression in the mound usually indicates the location of the mouth of the lateral. Fresh mounds are often dark because of the moisture in the earth that has been recently pushed out. Any grasses or herbs covered over by a mound are blanched (by loss of chlorophyll) after a few days, which provides another indication of its age. Trapping is most productive in fresh workings. In addition to the lateral tunnels used to push out earth, the gopher makes short, almost vertical laterals in coming to feed on surface vegetation. These often are closed with earth that does not rise above the adjacent ground surface. Gophers dig deeper tunnels in connec- tion with their nests, and may dig short, steeply pitched "sumps," possibly to drain adjacent tunnels. The nest is usually in a chamber about 8 inches in diameter; it is constructed of fibers of grasses and '-,**&*. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloratio
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