29 



matter of justice to the squirrels they should be given credit 

 for great service in distributing and planting the seeds of forest 

 trees. 



Muskrat (Ondatra zibethica zibethica)'. 

 Ingersoll names the muskrat among the mammals that rob 

 the nests of ground-nesting birds. 1 Dr. Abbott asserts that 

 muskrats sometimes eat young green herons that fall from 

 the nest. 2 Wounded ducks are said to be attacked occasionally 

 by muskrats, and some dead ducks are eaten by them, but 

 beyond this I have been unable to find any evidence that the 

 muskrat is destructive to birds under normal conditions. What 

 it may do when in abnormal numbers is shown by recent expe- 

 rience in Austria, where it has been introduced and is said 

 to have increased rapidly, devouring wheat and other cereal 

 crops, fruit and vegetables. It has almost ruined industries 

 of crayfish and carp breeding; has raided poultry, carrying off 

 young chickens, and has even attacked game animals. It un- 

 dermines railway embankments, ruins dikes and seems to have 

 become a first-class pest. Muskrats normally feed very largely 

 on vegetable matter and thus tend to prevent vegetation from 

 choking up ponds and streams. They eat mussels or so-called 

 fresh-water clams. Ordinarily the demand for their fur will 

 prevent abnormal increase. 



Mice. 

 The importance of mice as enemies of small birds and game 

 birds is not generally understood. If not held in check they 

 may quickly become the most destructive of all the agencies 

 for the suppression of birds. If an irruption of field mice 

 should occur in early summer they would destroy the grass 

 and clover, and the callow young of the small ground birds 

 that nest in the field would be left unshaded from the hot sun, 

 which would kill most of them even if they escaped the 

 swarming, hungry mice or the other enemies to which they 

 would be exposed. The eggs and young of game birds which 

 nest on the ground would not escape the latter fate. If deer 

 mice and pine mice were to increase half as fast as nature 



i Ingersoll, Ernest: The Wit of the Wild, 1906, p. 54. 



• Abbott, C. C: A Naturalist's Rambles about Home, 1885, pp. 188, 189. 



