36 
Table B-10. Minnesota--Estimated number of breeding ducks in the spring of 1979. 
Te ee te 
Unadjusted Adjusted Percentage 
population Visibility population change from 
Species index Factor index 1978 
Mallard 73,226 2.70 198,000 + 5 
Blue-winged teal 49,919 4.54 227 ,000 -11 
Other ducks 46,745 Peed 173,000 +2 
Tota] 169,890 598 ,000 - 3 
EEE 
Table B-11. Breeding population estimates for ducks in Minnesota in recent years 
based on aerial censuses corrected for visibility. 
: : _ pe 
Year Mallard Blue-winged teal All ducks 
eee me ee ee ere 
1970 111,000 153,000 316,000 
1971 96,000 153,000 331,000 
1972 69,000 100,000 258,000 
1973 104, 000° 136,000° 423,000° 
1974 98,000° 112,000° 404,000? 
1975 146 ,000 163,000 490,000 
1976 152,000 387,000 697,000 
1977 218,000 219,000 576,000 
1978 189,000 256,000 615,000 
1979 198,000 227,000 598 000 
/ | es 
2D rocedural changes in data compilation initiated in 1975 have been used for 
revision of raw data in these years. Values represented here differ Slightly 
from previous years. 
Total duck figures do not reflect the changes noted in footnote "a". 
