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                                                            cc Palmer 
                                                               Walcott 
                                                               Bell 
                    1940 REPORT ON DELTA DUCX STATION          Pirnie 
                                                               Hochbaum 
                                Aldo Leopold 
 
 
     This report is based on a visit at the station June 26 to July 4, 
 
and at Winnipeg July 5. I did not stop at St. Paul because Mr. Bell was 
 
out of town. 
 
 
                               (A) 1940 Work 
 
     This year's work is well organized and is noteworthy for the complete

 
teamwork among all the Delta personnel. 
 
     Research Projects. All of the research projects show good and some 
 
exceptional headway. The status of each is as follows: 
 
          Criteria of Sex and A   in Ducks. The discovery of cloacal 
 
extrusion as a means of sexing and aging live ducks is our biggest accomplish-

 
ment so far. The new technique has already spread far and wide. Its relia-

 
bility and its harmlessness to the bird are fully proved. It should be 
 
published this winter. 
 
          EE21oA7 of the Marsh. One more year should be added before publish-

 
ing this study of the arrival, courtship, nesting, brood behavior, ani summer

 
and fall movements of Delta ducks. 
 
          Identification of Dn YonA; Growth Curves. Now complete except 
 
for greenwing, baldpate, greater scaup, black duck, whistler, bufflehead.

 
None of these nest at Delta and the cooperators who promised eggs failed
to 
 
send them. All other gaps in the collection of skins will be filled by the

 
end of this nesting season. Will be ready for publication in the winter of
1941. 
 
          Nesting Study. 130 nests are being followed this year as against
100 
 
in 1939 and 25 in 1938. This is an excellent showing, especially since the

 
labor is carried "on the side" by the entire personnel.