4] 
The May breeding population of Area III was 438 pairs. According 
to our brood beat-outs, these birds produced 188 successful broods or a pair 
success of 43 percent. The average size of Class III broods was 6.1 young per 
brood, or 1,147 juveniles per 188 broods. This is a total population increase of 
131 percent as compared to 74 percent in 1954 resulting from a 25 percent pair success 
that year. In other words, a 10 percent reduction in breeding population in 1955, 
resulted in a production nearly double that of a population which was larger by 10 
percent in 1954. 
Table VIII. - Brood Counts, Area lV, 

Total 
Species June July August Production 
Mallard 10 26 (10)* 49 (5) 58 
Pintail 5 11 ( 3) 8 11) 
Gadwall 0 1 4 4 
Baldpate 0 12 ( 1) 19 (2) 19 
Blue-winged Teal 0 12 ( 4) 35 (3) 35 
Green-winged Teal 1 7 ( 2) 20 (7) 20 
Shoveler 0 2 3 (1) 5 
Redhead 0 Z 9 (1) 11 
Canvasback 8 9 13 15 
Scaup 0 0 11 11 
Bufflehead 0 1 3 3 
Goldeneye ] ] 0 1 
Ruddy 0 0 9 9 
Unidentified 0 4 (1) 7 7 
Total 25 88 (21) 190 (19) 209 
* Numbers in parentheses represent broody females whose 
broods could not be counted because of dense 
cover. 
The May breeding population of Area IV was 472 pairs. Brood beat- 
outs resulted in finding 209 broods or a pair success of 44 percent. The average 
size of Class [II broods was found to be 6.9 young per brood or 1,442 young per 
209 broods. This is an increase in over-all population of 147 percent compared to 
1954 with a pair success of 28 percent and an over-all increase in population of 
73 percent. Again in the case of this portion of the northern parklands, a 10 percent 
reduction in breeding population, produced twice the young that a larger population 
had produced the year previously. 
