River Surveys 
Approximately 76 square miles of Wisconsin rivers were surveyed by the same 
method applied to lake and marsh surveys. Some portions of river waters ware 
often wholly or partially concealed by trees but in the main these bodies of 
water were sufficiently open to give an accurats indication of resident breeding 
populations. Breeding population densities observed on the Mississippi and 
Wisconsin Rivers were disappointingly low. Breeding population densities on 
the St. Croix and Yellow River in Burnett County were appreciably higher and 
indicate relatively good breeding densities. Data obtained is submitted herewith, 
Aerial River Surveys-Waterfowl Populstion Densities 
a. 

oe 
Total Prs. Prs./Sq. Mi. Total Total Ducks Coot 
River Sq. Miles WS WCD FS WCD Ducks Coot per Sq. Mils 
Miss. LA 75 36 7° «#420.8 1.8 233 313 Bd, 7 
Wisc. 13.50 1 15 0.1 Taal 15 1.1 0 
Black 3.00 2 . C9 la? 5 3 te 0 
Grand 3.00 1 I O23 9.3 2 OG a4 0 
St.Croix 7.00 18 34. 2.6 2.9 40 : SF 0 
Yellow 4.80 15 ee Tel 103 21.5 0 
TAL 76.05 73 #167 0.96 SD 398 13 5.2 4el 


~ 
Species Composition as Indicated by Aerial River Surveys 
ape ED EE 





Lons Total® 
Lone Fe- Total* fFe- . Total Percent 
Speciss Pairs Males males Males males Unsexed Birds of Total 
Mallard 12 15 1 82 14 0 96 24.1 
Black 3 i ) Ms 3 2 9 203 
Gadwall 0 1 9) 1 0 oO. i 0.25 
Baldpats ) 0 0 Q 0 1.4 15 3.8 
Pintail Es 9) 0 8 iF 0 2 Oeh 
Be-w. teal 3 0 0 3 3 2 8 2.0 
Wood duck 8 1 0 13 7 0 20 5.0 
Ring-neeck i 0 0 3 aL, 0 4, 1.0 
Redhead 1 0 0 1 1 0 2 035 
Canvasback 0 0 0 0 @) 0 0 0.0 
Scaup 2 a 0 26 15 89 130 32.7 
Hooded merg. 1 0 0 1 1 0 2 0.5 
Am. merg. 0 HE 0 1 9) 0 1 0.25 
Ducks 
Unidentified 6 - - 1 a6 6 96 108 eel: 
TOTAL DUCKS 36 20 . 142 5a 204 398 100 ,0 
Coots 313 
*Tncludes summering ducks and flocked birds not esa de in Columns 
2-3. 
Methods of Computation 
In compiling information for the waterfowl census data the writer adhered 
to thse following procedures in classifying waterfowl: 
19. 7 . 5 
