nesting occurred on the river between Terry and Fallon. The only two islands 

 available for nesting in this section are readily accessible to predators 

 during low-water periods (such as in the early part of the nesting season). 

 The unbraided nature of this section contrasts with the more braided section 

 between Sanders and Forsyth (figure 25). There does not appear to be a 

 direct relationship between the number of islands in a given section of 

 river and the size of the goose breeding population. Those sections with 

 the most islands per length of thalweg (those above the mouth of the Bighorn 

 River) did not have the highest densities of nesting geese. Upstream from 

 the Bighorn, the size and vegetative characteristics of the islands, as well 

 as that many are continuous with the banks during low water, apparently make 

 them undesirable for nesting. 



The length of shoreline bordered by agricultural land in a given 

 section did not correlate well with duck numbers observed, probably because 

 ducks concentrated in sections where picked cornfields were available for 

 field-feeding. Because the agricultural vegetation type included all crop 

 types and was not limited to cornfields, this relationship was not apparent. 



During the period that eagles were present, concentrations occurred 

 in areas having a readily-available food source. Because the location of 

 these food sources was not directly related to the river bottom's physical 

 parameters, eagle distribution was largely independent of vegetation types 

 and island characteristics. 



70 



