15 



adjohiing ones amounts to throwing away time and money. There is 

 great need of systematic effort to check the increase of both rabbits 

 and prairie dogs. The amount of forage annually destroyed by them 

 is enormous. The loss of grass is distributed among a large number of 

 stockmen, and so is not felt in its entirety by individual owners, but the 

 loss in taxable values to the counties and the State is no small one. 

 The grass eaten by 100,000 rabbits would support 20,000 sheep, and 

 there are nuxny counties in southern Texas where this would be a very 

 moderate estimate of their numbers. In the heart of the prairie dog- 

 infested region the writer has seen extensive villages where, at a very 

 conservative estimate, tliere were from 2,000 to 5,000 prairie dogs to the 

 square mile. ]S"ow, on a square mile of land so infested the dogs eat 

 and defile grass enough to maintain from 100 to 250 sheep per annum. 

 Prairie dogs will not tolerate tall grass near their burrows, probably 

 partly on account of the cover thus given to their enemies, and partly 

 because these grasses are better relished by the dogs. They dig up the 

 roots of all of the more succulent species, like the sedge grasses, and 

 permit only the low turf formers to remain. The dog- village grasses 

 are needle grass, curly mesquite, woolly oats {Triodia avenacea), and, in 

 western Texas and New Mexico, hard grass {Scleropo(/on hrevifoHus), 

 a harsh-stemmed turf-former seldom found in abundance anywhere 

 else. Some of the grasses that occupy the prairie dog-infested land 

 are intrinsically valuable for grazing, especially in winter when cured 

 on the ground, but they lack the bulk of the taller kinds which would 

 grow on the land if the prairie dogs were killed. Lands occupied en- 

 tirely by these grasses are not and can not be called productive; they 

 have reached almost the lowest stage of deterioration, and are next to 

 valueless for grazing purposes. The extermination of prairie dogs 

 and jack rabbits means a great deal if the grazing industry is to be 

 developed to its fullest extent. 



DETERIORATION THROUGH INCREASE OF "WEEDS. 



Another factor which is tending to decrease the carrying capacity of 

 the ranges, as a whole, is the rapid spread of prickly pear and thorny 

 shrubs in the South and of the mesquite bean on the table lands and 

 higher prairies. At certain times or in certain seasons both the prickly 

 pear and the mesquite bean are of some value as sources of food, but 

 their increase can not be looked upon as wholly beneficial. 



PRICKLY PEAR. 



The iiat joints of the prickly pear {Opuntia engelmanni) are mucilagi- 

 nous and watery, and in times of drought serve to some extent as 

 food, or, more especially, water. Cattle and sheep may be kept alive 

 for several months on prickly pear when all other forage has become 

 dried and broken and has blown away — a state of affairs that often 

 occurs duriug a severe drought. At such times, if the stockman 



