208 
Class I wlass [I Class III 
1952 ye © ee at ee ee ee 
No. broods: 86 117 53 
Percent: 33.6 45.7 20.7 
Average Size: 7.31 7.76 6.64 
1953 
No. broods: 84 44 8 
Percent: 61.8 32.4 5.9 
Average Size: 7.34 7.20 6.16 
This year 61.8 percent of the broods observed were of the Class I or downy 
size compared with 33.6 percent for this Class last year. Last year more older 
broods were present: 45.7 percent were Class II and 20.7 percent w:re Class III. 
This year 5.9 percent were of the larger Class III size. Average brood sizes are 
similar for the 2 years, 
In view of the larger portion of broods in Class I as compared with 1952, it 
appeared that the brood counts this year were made earlier phenolopgically. After 
these brood counts which were comparable with 1952 counts had been summarized 
in mid-July, it appeared that waterfowl nesting had suffered losses and delays due 
to the adverse weather conditions of May and June. 
The extent of renesting or late nesting could not be known until later when 
additional brood counts were made. 
Three brood counts were completed during June, July, and August on 27 water 
areas and pothole transect routes. Broods were aged according to the 7 classes 
discussed by Blankenship et al in Techniques for Brood Production Studies. Data 
from each water area or transect route were handled individually by species. Broods 
from the second count were eliminated from the usable data if they would have hatched 
within 6 days of the time when first-count broods of the species were estimated to 
have hatched. 
The following example illustrates the procedure used: Two broods of teal from 
the first count on a slough were estimated to have hatched on June 27. On the second 
count 5 broods of teal were counted which were estimated to have hatched between 
June 18 and July 2. Two of the 5 broods would not be used since it is possible that 
they had been recorded on the first count. This procedure was also used in handling 
the data of the third counts. 
A total of 354 broods was usable from the counts on the 27 water areas and - 
transect routes after the previously described process of elimination had been carried 
out. Data on the probable age of broods in each plumage class were not available for 
all species; the exceptions being ringneck, ruddy duck, goldeneye and wood duck. The 
probable ages listed for lesser scaup were assigned to these broods and to aged but 
unidentified broods. The ages for lesser scaup were used since the flight age of this. 
species is intermediate between that of the extremes (blue-winged teal, 40 days; 
canvasback and redhead, 60 days). A small number of the broods were aged only 
as Class I, Class II, or Class III. These broods were apportioned as equally as 
possible to the various sub-classes, The 354 usable broods were distributed as 
follows by species: 
