DRY FOREST MARGIN 269 



I. SUBTERRANEAN-GROUND STRATUM 



Certain earthworms, cicada nymphs, and root-eating grubs belong 

 here. This is the regular breeding-place of the skunk {Mephiti: meso- 

 tnelas avia Bang). According to Seton (143) they go in droves of six or 

 eight, and as many as fifteen sometimes occur in a winter den. Accord- 

 ing to Seton its food consists of various insects, grasshoppers, crickets, 

 meadow mice, snakes, and crayfishes. The short-tailed shrew in primeval 

 conditions breeds chiefly in such tangles of bushes. It digs in moss 

 and fallen leaves and loamy soil, and follows mouse galleries. According 

 to Wood (21) it eats many mice. Seton (143) states it feeds on isopods, 

 earthworms, etc. Its enemies are hawks, lynxes, and weasels. 



Franklin's ground squirrel (Citellus franklini Sab.) burrows into the 

 ground deeper than the ground squirrel of the prairies, but is otherwise 

 similar in habits. It is gregarious and stores grain for winter. The 

 chipmunk (Tamias striatus griseus Mear.) is a typical forest margin 

 animal. It nests in the ground, as a rule in burrows about 6 to 10 ft. 

 long and running diagonally down to a depth of 2 to 3 ft. (21). It stores 

 nuts for winter. The jumping mouse (Zapus hudsonius Zim.) is one of 

 the most characteristic residents; it moves by great leaps and steers its 

 flight with its tail. The woodchuck should probably be counted here, 

 though it belongs deeper in the forest than any of the others. The weasel 

 is common in this situation, though it is perhaps more abundant along 

 streams (Wood). 



The ground stratum supports many of the small animals of the 

 adjoining forest, such as centipedes, camel crickets, etc. The cottontail 

 is one of the chief residents, as it usually breeds in such situations. The 

 common shrew (Sorex personatus St. Hil.) (21) breeds on the ground, in 

 stumps, etc. All of the mammals recorded in the preceding stratum 

 feed here when suitable food is present. A considerable number of 

 mammals commonly regarded as belonging to the forest are said to prefer 

 thickets. The Virginia deer is one of these. It is probable that the elk 

 was somewhat similar in habits. 



The bobwhite and mourning dove (occasionally) breed in these situ- 

 ations, the former often falling a victim to the weasel (Wood). The 

 high forest margin was probably a favorite location for the huts of the 

 aborigines. Some of the early travelers record huts around the edges of 

 the prairies. Such locations would supply shelter and firewood, etc., as 

 well as sunshine. 



2. FIELD AND SHRUB STRATA 



Here the ground-cherry, milkweed, and thistle have a characteristic 

 fauna. On the milkweed are the larvae of the monarch butterfly, the 



