1. The Social Use of Space 



85 



Table IX 



Invasion of Redbacked Mice into an Area Subjected 

 TO Continuous Removal Trapping 



Radius to Proportiou of total 

 Location outer edge area from which 



of area trapped mice originated 



Catch 



Expected Observed 



make a test of significance superfluous. This, of course, only proves that 

 the formulation is not wrong; it does not prove its validity. In the absence 

 of any evidence to the contrary, the formulation will be accepted as ap- 

 proximating reality, and I will proceed with exploring further questions. 



First, what about w = 302 feet? Webb and Rosasco (1953) and Patric 

 (1958) offer considerable evidence indicating that the home range sigma 

 for Clethrionomijs must be close to 50 feet. Thus, w = 6. Oct. According to 

 the independently arrived at formulation, vocal signals can be detected 

 up to a distance O.Oo- from the emitter (Fig. 18 and Section VII, C). Also, 

 the diameter of the constellation approximates G.Oo- (Fig. 27, Section 

 VIII, C). Recall that the constellation represents the inferred basic unit 

 of social organization among such animals. Thus all members of constella- 

 tions which overlap the circular line, or even just touch it although the 

 home range centers of their members all live peripheral to the trapline, 

 can detect a signal void centripetal to the trapline. 



Before going on, I would like to emphasize that the diameter of 1124 

 for the circular trapline was dictated by the desire to ensure that mice 

 arriving at the trapline would not be able to hear others across the void on 

 the other side. In fact, if 302 feet does represent the threshold distance of 

 perception, then the angle of signal void facing a mouse arriving at the 

 trapline would be that angle subtended by chords of 302 feet from that 

 point, in this case 159 degrees. 



The existence of constellations assumes prior development of bonds of 

 attachment among its members. Once the central cross of traps and the 

 circular trapline had removed all mice exposed to it, survivors of constella- 



