Area practically denuded of grass by prairie dog--Wescalero Indian Reservation, New Mexico. [Illustration] Dogs on leash and tin cans rattling in the wind are some of the primitive methods employed by Indians in futile attempt to save crops from ravages of prairie dogs in the Southwest. [Illustration] [Illustration] Indian cornfield totally destroyed by prairie dogs. [Illustration] Cotton and corn fields damaged by prairie dogs in northwest Texas. [Illustration] [Illustration] Side of basin denuded by prairie dogs--devastation being rapidly completed by erosion. Cochetopa Forest, Colorado. [Illustration] Prairie dogs prepare an ideal condition for the start of sheet erosion on hillsides by denudation of vegetative cover. Note lack of vegetation. Erosion once started is accelerated by other factors as shown on page 11. [Illustration] [Illustration] Overgrazing, wind, and flood-- [Illustration] resulting in gullies and arroyos. [Illustration] [Illustration: Interpreter explaining to Indian farmer in Arizona how to expose poisoned grain. The Indian, at the left, stated that he picked up 180 dead prairie dogs over an area estimated at about 200 acres around his 48 acre farm.] GROUND SQUIRRELS [Illustration: Ground squirrel damage. Semidesert type country. Note squirrel at mouth of burrow.] [Illustration: E.C.W. ground squirrel control crew--Payette National Forest, Idaho.] [Illustration: E.C.W. crew at work on Umatilla National Forest, Washington.] [Illustration] Ground squirrel burrows become waterways during a rain and are the beginning of this type of erosion. [Illustration] Papago Indian Reservation, Arizona. POCKET GOPHERS [Illustration: Typical mountain range land, heavily infested with pocket gophers--Davis Lake, Oregon--before treatment.] [Illustration: Same area one year later after pocket gophers were brought under control and native grasses had had a chance to reseed.] [Illustration: Farm land infestation--Texas. Mounds represent pocket gopher workings.] [Illustration: Mountain meadow in Utah. Picture taken just after snow had melted in spring. Ridges of dirt show extent of pocket gopher operations under snow in winter.] [Illustration: Pocket gopher infestation--Louisiana.] [Illustration: Break in terrace caused by pocket gophers burrowing through embankment.] [Illustration: Pocket gopher infestation along highway.] [Illustration: Flood water starting through a pocket gopher burrow passed under a cement highway,--] [Illustration: Flooded the barrow pit on the opposite side of road, and poured into farmer's field, leaving a deep wash as a monument.] [Illustration: Damage starting from pocket gopher hole in irrigation canal bank--] [Illustration: Soon results in bad breaks causing expensive repairs and loss to crops through failure of irrigation water.--] [Illustration: And is often responsible for start of gullies.] KANGAROO RATS