CONTENTS 
Abstract . iv 
Introduction . 1 
Singing-Ground Survey . 1 
Source of data . 2 
Method of analysis . 2 
Weighting factors . 3 
Results . 3 
Recommendations to cooperators . 4 
Random sampling in Michigan . 4 
Wing-Collection Survey . 6 
Source of -wings . 6 
Age and sex determination . 7 
Method of analysis . 7 
Weighting factors . 7 
Results . 8 
Acknowledgements 
9 
