
Percent of all 
successful nests 
‘started 
100 
80 


0 = . , 
Apr. 10 Apr. 30 May 20 June 9 June 29 July 19 Aug. 8 
Date started 
Percent of all 
successful nests 
started 
100 
80 
60 
Apr. 10 Apr. 30 May 20 June 9 June 29 July 19 Aug. 8 ~ 
Date started 
1950 1951 1952 | 1953 
Figure 13.--MALLARD AND PINTATL: FIRST EGG LAYING IN 
SUCCESSFUL NESTS, 1950-53 
29 
