SS ee eS SS Dn SS aS ST ee 
CENTRAL FLYWAY 
Species Composition - Central Flyway States - Continued 



Percent of Birds Identified Percent 
Species 1956 1957 Change 
Blue Goose 6 ,8 - 20.1 
Gadwall 5 9 ~ 6.6 
White-fronted Goose 3 4 = 2523 
Shoveler 3 4 +- 22.0 
Goiceneye 2 4 + 22.1 
Canvasback hi ar? ~ 37.6 
Biue-winged Teal Tr. Tr. - 
Ruddy Duck Tr, Tr. ~ 
Ringneck Tr. ai - 
Bufflehead Tr. Tr. - 
Moitled 8B aa Tr, “ 
Woecd Duck ope LY. - 
Trumpeter Swan Tr. Bis S 
Whistling Swan Be ee Tr. ? 
Total 100.0 | 100.0 - 44.1] 

Summary of Central Flyway Winter Survey Data 
Due to a lack of data from the Mexican wintering areas there 
is reason to doubt that the data for some species in the preceding table 
are representative of changes in wintering population. However, some 
species winter almost wholly within the United States and some con- 
clusions can be drawn from this group as follows: 
Ducks ~ Although the over-all duck index decreased 45 percent as 
; compared to 1956, it is significant to note that the decrease 
was mainly among pintails, redhead, scaup, and baldpate, all 
of which are regularly found in large numbers in Mexico. On 
the other hand. the mallard, which winters entirely within the 
United States, showed an increase of 15 percent. 
