Part II.] NATURAL ENEMIES OF BIRDS. 231 



and then reared by hand until nearly full-grown, when released 

 climbed an apple tree to a robin's nest, took a young bird and 

 ate out its brains. The red squirrel appears to be as fond of 

 meat or fish as is the cat. It eats the trappers' baits, gnaws 

 the carcasses of animals that he has skinned, takes meat, suet 

 and other fats put out for birds in winter, and, like all other 

 squirrels, feeds more or less on insects in spring and summer. 

 Many of my correspondents have reported that they have 

 seen it robbing the nests of birds.^ Two have noted it as 

 catching adult birds in the air as they flew at or by it, but in 

 all my experience in the woods I have not been able to corrob- 

 orate this. There is some evidence in favor of the theory that 

 individual squirrels which acquire the habit of robbing birds' 

 nests are the chief culprits. I am now inclined to the belief 

 that nest-robbing sometimes becomes a habit with certain 

 squirrels, and that in some places the habit is communicated 

 to many individuals and perhaps over considerable areas, while 

 in other localities it is not common. Such practices are likely 

 to spread as a consequence of any undue increase in the 

 numbers of squirrels, and are in a fair way to become wide- 

 spread, when such increase begins to outrun the normal food 

 supply. This squirrel is said to destroy the eggs of the ruffed 

 grouse, and Dr. B. H. Warren records the killing of an indi- 

 vidual in the act of carrying off a small chicken from a coop. 



Gray Squirrel {Scmrus carolinensis leucotis). 

 We have protected gray squirrels by destroying their greatest 

 enemies, the red-tailed hawk and the great horned owl. There- 

 fore, wherever shooting is forbidden the gray squirrel may be- 

 come numerous, even in some cities, where there are trees 



1 Most writers on the habits of mammals seem to agree that the red squirrel is a nest-robber. 

 John Burroughs says that he thinks that the mischief it does can hardly be overestimated (Signs 

 and Seasons, 1886, p. 92). Stone and Cram say that in summer it robs birds' nests high and low 

 (American Animals, 1902, p. 173). Ernest Ingersoll asserts that it destroys far more birds' eggs 

 and young than any other squirrel, and that not even the Baltimore oriole's nest is safe from 

 it (Our Animal Competitors, 1911, p. 129). Ernest Harold Baynes avers that he has known so 

 many nests destroyed by it that he will not allow one of these animals in any place where he is 

 trying to attract birds (Wild Bird Guests, 1915, p. 28). On the other hand. Mason A. Walton 

 asserts that in his neighborhood birds do not fear the red squirrel, which occasionally examines 

 nests but never, so far as he has observed, molests thom. He tells of one which investigated 

 a chickadee's nest frequently and did no harm, and another which examined a vireo's nest in 

 which young were later safely reared. He asserts that nineteen nests built near bis cabin in one 

 season were not troubled by squirrels (A Hermit's Wild Friends, 1903, pp. 68, 70, 98). 



