24 John B. Calhoun 



closely approximates Curve I and the observed data than does Curve II. 

 At present parsimony demands assuming only that the farther an animal 

 moves from his home range center, the more likely it will terminate an 

 outward trip and respond to stimuli near the place of stopping. Extremely 

 careful observation is required to determine if animals tend to wander still 

 farther about the points of termination of trips as these points occur 

 farther from home. 



B. Travel-Path Home Range 



Captures or responses represent only one method of assessing home 

 range. I have indicated that one assumption regarding behavior is that on 

 the outward trip from home and on the return trip to home, the animal is 

 in a preceptually blind state during which static stimuli fail to elicit 

 responses. And yet it is possible to observe and record the presence of such 

 nonresponsive individuals on this outward and return trip. Utilizing Eq. 

 (19) and considering the effect of the geometry factor in the sense that the 

 observer in a two-dimensional field can record an animal only if it passes 

 directly by the observer, and assuming that the amount of wandering at 

 end of trips is minimal, the equation for the cumulative probability of ob- 

 serving an animal during its travels. Curve III, becomes: 



Cumin = 1 - (1 + 7?)e-« (27) 



Data for Curve III with the a constant = 0.44 are shown in Table III and 

 on Fig. 8. Obviously, if "captures" represent such observations, the animal 

 will appear to spend more time closer to home. Leopold et al. (1951, Fig. 50) 

 provide data on home range based upon visual observation of marked mule 

 deer. They presented their data in terms of number of observations within 

 successive 100-yard bands from the site of capture. The actual home range 

 center will be on the a\'erage somewhere to the right or left of the hne of 

 length d connecting the point of capture and the point of later observation, 

 the actual radial distance from the true home range center would be K • d/2 

 when K is between 1 .0 and 1.414. Without going into the origin of K, it is 

 still apparent that the distances given by Leopold et al. (1951) can be 

 utilized as approximating proportionality to radial distances of observa- 

 tion from the home range center. The cumulative probabilities of observa- 

 tion for 102 observations of males and 103 observations of does and fawns 

 are with distance, respectively: 100 yards (0.363,0.495), 200 yards (0.500, 

 0.815), 300 yards (0.678, 0.952), 400 yards (0.726, 0.980), 500 yards 

 (0.862, 1.0), 600 yards (0.862,—), 700 yards (0.932, — ), 800 yards 

 (1.0, — ). Noting that 0.50 of the males were observed within 200 yards 



