124 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Attention has been given also to the habits of the California ground 

 squirrels, especially durmg the breedmg season, since it is evident 

 that the most effective way of reducing their numbers is to kill them 

 prior to the time they have young, especially as they are very prolific 

 and have from four to eleven at a birth. 



RODENTS IN RELATION TO REFORESTATION. 



One of tlio most important of modern forestry problems is the 

 economical reforestation of treeless areas within our National Forests. 

 When attempts at reforestation were made on a large scale by the 

 Forest Service, it was found that, after seeding, on an average about 

 half the seed planted was dug up and eaten or carried away by mice 

 and chipmunks, thus adding largely to the cost of the undertaking. 

 In some localities as high as 70 per cent of the seed has thus been lost, 

 which loss is prohibitive of the work. As these rodents are exceed- 

 ingly numerous within all forest areas and clearings, attempts at seed- 

 ing without protecting the seed in some way or largely reducing the 

 number of rodents proved practically hopeless. Accordingly, at the 

 request of the Forest Service, experiments were begun by the Biolog- 

 ical Survey for the purpose of finding a remedy. ^lany experiments 

 were made to protect the seed with a coating of such substances as 

 red lead, copper sulphate, and coal tar, but they failed. Attempts to 

 poison the animals, however, have proved very successful. Oatmeal 

 mixed with strychnine and water, or wheat coated with hot tallow 

 mixed with strychnine as a protection against rain or moisture, proved 

 very effective. The poison is distributed over the tract to be planted 

 several days in advance of seeding operations, when the subsecjuent 

 loss by rodents is inconsiderable. It is believed that the adoption of 

 this plan -vnll solve one of the chief difficulties connected with refor- 

 estation. 



RODENTS AND SPOTTED FEVER. 



It is believed that the dreaded spotted fever, wliich prevails in 

 certain sections of the Rocky Mountain region, is transmitted to 

 human beings by ticks which harbor on certain of our native mam- 

 mals. As having an important bearing on the attempts to eradicate 

 the disease, it is extremely important to ascertain the species of 

 mammals concerned in its transmission. Hence the Survey was 

 asked to cooperate with the Bureau of Entomology and the officials 

 of the State of Montana in an investigation. Accordingly, two assist- 

 ants of the Survey spent several months in Bitterroot Valley, Mon- 

 tana, trapping mammals, especially the smaller rodents, and studying 

 their habits with a view to the discovery of the species that harbors 

 ticks. So far fever ticks have been found on twelve species of wild 



