180 
Table VII. - Comparison of Waterfowl Pairs and Broods on-the White River Plateau, 
Colorado, 1952 and 1953 . 
No. Production 
Breeding-Pairs No. Broods No. Young Per Sq. Mi. 
Species 1952 1953 1952 1953 1952 1953 1952 1953 
CC 
Mallard 480 440 380 360 2,040 2,080 5.7 5.8 
G-w. Teal 100 20 60 20 400 100 1.1 3 
Lesser scaup - 20 - - - - - - 
Naan er rr SS yr Ss i PSPS 
Total 580 480 440 380 2, 440 2,180 6.8 6.1 
San Luis Valley 
In general, water levels in the San Luis Valley were far below those present in 
1952. This can be attributed directly to the low amount of winter precipitation on 
drainages entering the Valley as compared to 1952. Consequently, nesting habitat was | 
greatly reduced, and nesting pairs were found to be concentrated on permanent water 
areas. 
Results of the 1953 aerial survey are given by summary form in Table VIII. 
Unfortunately, no measured data are available for the 195] count when low water 
levels were present in the Valley as a result of a prolonged drought. The 1949, 
1950, and 1952 results are given for comparison, 
A gross comparison of 1952 and 1953 production shows a decrease of approx- 
imately 43 percent in 1953, The average number of young per brood shows a decrease 
of 18 percent, Beyond a doubt, the low water levels resulting in limited nesting habitat 
are responsible for the.decrease in production. 
Table VIII. - Comparison of Production in the San Luis Valley, 1949, 1950, 1952 and 

1953 
Number of Number of Average Number of 
Year Broods Young Young Per Brood 
1949 57 353 6.20 
1950 100 522 © 5.22 
1952 115 809 7.03 
1953 81 462 5.73 
South Park 
Intensive studies of waterfowl production, and the establishment of permanent 
aerial transects will not begin in this area until 1954, The only information available 
from South Park this year, therefore, is the results of a preliminary ground survey 
and one aerial census of breeding-pairs., These are listed in Table IX revealing that 
at least 43] pairs will currently attempt nests in the Park, This is believed to be 
lower than past years due to less water area in the Park in 1953. 
