In the Central Flyway, a sample of 21 wings was collected in 
the vicinity of the Lower Souris National Wildlife Refuge in North 
Dakotae These wings indicated a low age ratio, 0.82 immature per 
adulte In a sample of 50 mallard wings collected in Colorado, the 
age ratio was somewhat higher, 1.14 immatures per adult. 
In the Pacific Flyway, mallard-wing collections were made in 
the vicinity of a number of Federal refuges. Near Nampa, Idaho, a 
ratio of 1.61 immatures per adult was observed in a sample of 89 
wings. Age ratios in collections from this area decreased as the 
Season progressed. At Bear River Refuge, Utah, the very low age 
ratio of 0.37 immature per adult was observed in a sample of 140 
wings. Twenty-one mallard wings were collected in the vicinity of 
Fallon, Nevadas This sample revealed an age ratio of one immature 
per adult. 
In California, good samples of mallard wings were collected at 
three locations. Near Tule Lake, the age ratio was very low, 0.35 
immature per adulte Farther south, near Willows, the age ratio 
was higher, 1.61 immatures per adult. Im the vicinity of Merced, 
still farther south, the age ratio was 2.57 immatures per adult, 
one of the highest observed in this study. 
The reason for the pronounced difference in mallard age ratios 
among the three California samples is one of the most perplexing 
questions arising from this study. Refuge Branch personnel and the 
Pacific Flyway Representative, John E. Chattin, offered possible 
explanations for the differences. Chattin (letter of February 25, 
1957) pointed out that age ratios among mallards banded prior to 
the hunting season had for many years consistently shown the same 
differences in age composition as shown in the wing-collection 
sample. Age ratios at Tule Lake always were substantially lower 
than those in the two areas farther southe He stated, "one might 
theorize from looking at the current results that immature 
mallards show a strong tendency to move to southern or terminal 
wintering areas at a faster rate than adults. Adults, on the other 
hand, tend to remain farther north on migration areas, longer by 
reason of being better equipped to care for themselves". This 
theory would explain why the highest age ratios occurred at the 
most southern collection point. The results of the wing collection 
do not support this hypothesis, since age ratios in Louisiana were 
almost as low as those farther north in Arkansas, Missouri, and 
Illinois. Furthermore, the data in Table 37 indicate that age ratios 
did not change substantially in the three California collection areas 
during the seasone The pronounced differences among the three areas 
were much the same throughout the season. The possibility that the 
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