
In order to assure receiving 9) usable reports in any one year, 
it appears necessary to obtain coverage of at least 145 areas, thus’ 
allowing for 35 percent to be rejected in statistical studies. By 
continuing to impress on all participants the importance of cover- 
ing the same area every year, and of covering the most productive 
areas on foot, we should be able to reduce the number of rejected 
counts to some extent. However, there will always be unavoidable 
circumstances that will disrupt coverage, and no reduction in effort 
would be justified until it has been demonstrated that the neces- 
sary number of areas will continue to be covered. 
64 
