(2) Conversely, the percentage of utilization of water areas by waterfowl 
ross 5.1 percent, i.e. from 12.8 percent in 1948 to 17.9 percent in 
1949. 
(3) Although only 17.9 percent of the water areas were occupied, 33 per- 
cont of the total acreage involved was occupied by waterfowl. 
(4) Water areas occurred within the following size classifications in 
the following percentages: 
0 to 1.0 acres - 5% 10.1 to 25.0 acres - 5% 
1.l to 5.0 " ~~ 264 Over 25.0 n= «5% 
5ol to 10.0 " — (a ui 
Because temporary and intermediates water areas were scarcs, breeding water- 
fowl were obviously concentrated more heavily on permanent water areas. This 
seemed particularly trues of the large marshes where relatively heavy (for Wis- 
consin) breeding densities were found (See below). In the opinion of the writer 
the significant part of this phenomenon is that the disappearance of those water 
areas had already taken place by the time the waterfowl breeding season had begun. 
Consequently, most Wisconsin waterfowl are producing on areas which have perma- 
nent water; thus waterfowl production in Wisconsin during 1949 should be enhanced 
somewhat becauss drought conditions should havs little or no effect on the 
population. Moreover, concentration of waterfowl on large areas may result in 
reduced losses because of predation and farming practices. 
Asrial Survsys 
Methods 
All acrial transects and river surveys were flown only once, and all lake 
surveys wers flown only oncs, with the exception of five lakes in southeastern 
Wisconsin which were coversd twice to see how closely data compared. Data on 
these five lekes, which were about average in population densities, have been 
included for both flights. 
Cross-Country Asrial Transscts 
Cross-country asrial transects were flown during ths month of May as 
dsscribed above. It is presumed that data obtained vie asrial census transects 
are most representative indicators of actual waterfowl breeding populations in 
the State since ths method is most mechanical in: coverage. However, ground 
census correlated with aerial census indicates clearly that a pronounced srror 
is'made in censusing blue-wingsd teal via air travel. It is probable that green- 
winged teal, pintails, and possibly some female diving ducks also are missed via 
this method. Aerial and ground coverage at Horicon, where marsh cover is about 
as dense as sncountsred anywhere in the Stats, show discrepancies on almost all 
species of waterfowl. 
A summary of information obtained on cross-country aerial transects is 
submitted herewith. 
18? 
