l6o ECONOMIC MAMMALOGY 



and provides them in cooperative work in various regions as they are 

 needed. There are also some men of experience in such work in the 

 employment of various states, as well as some "unattached" individuals. 



Some species so useful that their protection is very desirable, under 

 certain circumstances become locally so destructive that some method 

 must be adopted to prevent their depredations or to minimize the 

 damage resulting therefrom. There are often means of controlling their 

 pernicious activities without resorting to their wholesale destruction. 

 For example, the beaver is a valuable fur-bearer, and most of the trees 

 it cuts for food and for use in the construction of its houses and dams 

 are of little value, but sometimes, where such trees are scarce and others 

 are accessible, it attacks fruit, shade or other valuable trees. These may 

 be protected by woven-wire cylinders placed about them at a distance 

 of a few inches, 3 feet high, supported by substantial stakes. Woven 

 wire also makes good beaver fences. Their building dams so high as to 

 flood valuable adjacent land may be prevented by placing drain pipes in 

 the dams, directions for which have been published. 2 



Woven wire may also be used to prevent muskrats and other useful 

 animals from damaging gardens and burrowing into embankments, 3 

 and to protect poultry from weasels and skunks, 4 which are very use- 

 ful as enemies of rodents and insects. Nests of some small species of 

 birds may be protected from cats by woven wire of mesh large enough 

 to admit the birds but too small to admit cats, set far enough away 

 to prevent cats from reaching the nests with their paws. Cat-proof 

 poultry-yard fences are difficult to construct on account of the climbing 

 ability of the house cat, which will surmount a woven-wire fence, or, 

 if there is a tree near-by, it will climb the tree and drop into the en- 

 closure from a limb. Forbush says that an effective fence may be made 

 by use of six-foot woven wire set close to the ground at the bottom, 

 with a three-foot twine net above, fastened at the lower edge to the 

 top of the woven wire, making a fence nine feet high. The net baffles 

 the cat by giving beneath its weight. 5 



Deer and elk, though classed among the useful species, sometimes do 

 some damage to gardens, which may be prevented by good fences. 

 Lantz says that an elk-proof fence should be five or six feet high, but 



2 Bailey, Beaver habits and experiments in beaver culture, U. S. Dept. Agric. Tech. 

 Bull. No. 21, pp. 13-14, 30-31, 1927; Beaver habits, beaver control and possibilities 

 in beaver farming;, U. S. Dept. Agric. Bull No. 1078, pp. 11-12, 1922. 



3 Lantz, The muskrat, Farmers' Bull No. 396, pp. 34-35, 1920. 



4 Bailey, Farmers' Bull. No. 335, p. 28, 1908. 



5 Forbush, The domestic cat, Massachusetts State Board of Agric., Econ. Biol., 

 Bull. No. 2, p. 88, 1916. 



