b. 
Ce 
Improved or expanded breeding-ground coverage in the 
United States and Canada to determine the size and 
distribution of breeding populations. 
A corollary to "b'' is expanded banding on the breed- 
ing grounds to determine the similarity and variance 
in the migrational characteristics of birds from 
different areas. 
In view of the important differences in the movements 
between ages and sexes as found in other species, it 
is recommended that all future black~duck bandings 
include accurate records of sex and age. 
~18- 
