1936] MAMMALS OF OREGON 221 



long waterway to the open water and begin to get a part of their 

 own food from tender plants, twigs, and leaves. They remain with 

 the mother during at least the fall and first winter, and if un- 

 disturbed probably longer if the food supply is ample. The rela- 

 tion of the males to the family life is not fully known, but they are 

 sometimes found with the mother and larger young and are prob- 

 ably on friendly terms with their various families. 



Food habits. Beavers are purely vegetarian, feeding mainly on 

 bark, twigs, leaves, roots, and a great variety of water and shore 

 plants. Aspens, cottonwoods, and willows are their principal tree 

 food; these are cut along the shores, and the bark is eaten from 

 the branches and the small trunks. In autumn the branches and 

 sections of small trunks are cut and stored in masses in deep water 

 near the houses or bank dens, where they are accessible all winter 

 under the ice, but much winter food is also obtained from roots 

 and water plants along the banks and on the bottoms of ponds and 

 streams. During the summer much of the food is from green vegeta- 

 tion in the water or on the shores and few trees are cut except as 

 needed for building. Coniferous trees are rarely cut and not gen- 

 erally used for food. 



Beavers eat large quantities of coarse food and under favorable 

 conditions become moderately, and sometimes extremely, fat. 



Economic status. In past years the beaver has been the most val- 

 uable fur animal of North America, and with proper control and 

 management might well take again that place among fur bearers. 

 While in many places beavers do serious damage and ought not to 

 be encouraged, in suitable localities on public or private lands where 

 they can be fenced and supplied with the right kind of food they 

 should afford profitable returns in fur and meat. Great care should 

 be taken, however, to stock areas with animals producing the dark- 

 est, most valuable fur, as it is just as easy to raise high-priced as 

 low-priced beaver fur, and there is a wide range of prices between 

 the pale and the very dark beaver skins. As a private industry 

 beaver farming promises to be a complete success, but many of the 

 details have not yet been worked out, and if undertaken it should 

 be at first on a small scale with careful experimental advances 

 (Bailey, 1927). 



Since 1924 only partial protection has been given beavers in Ore- 

 gon, and most of the animals have been destroyed. 



The report of the district forester for Oregon, dated February 14, 

 1930, says : 



The open season on beavers in Oregon has proved an expensive mistake and 

 every effort should be made to repeal the law. The present law allows trap- 

 ping everywhere except on the national-forest land. However, the patented 

 land is so intermingled that this restriction has no effect. A check on the 

 raw furs shows that most of the beaver were caught before the fur was 

 prime. This was because every trapper was afraid every other trapper would 

 get in ahead of him. The number of beaver in the State has been reduced 

 almost to the vanishing point and this has affected stream flow, fish, grazing-, 

 and erosion to a serious degree. The beaver dams originally held back the 

 run-off on the heads of streams, supplying the irrigation sections of eastern 

 Oregon. The dams are now gone. These dams originally formed rearing ponds 

 for the small fish and helped to restock the streams. * * * Erosion fol- 

 lowed and many of our best grazing areas have changed in type from wet 

 meadows of high carrying capacity to a dry, rapidly eroding type of extremely 

 low or no carrying capacity. 



