70 



Table VIII. - Nest Versus Brood Data, 
1952 1953 1954 1955 
la 
Mallard 
Nesting success in percent 56.9 48.9 24.1 38. 
Percent of successful females 46.2 39.1 21.3 42, 
All Species 
Nesting success in percent 49.5 50.1 28,0 41,2 
Percent of successful females 42.4 42.8 +87 45. 
From either set of data we would conclude that there was no great 
change in rate of reproduction between 1952 and 1953; that there was a decided 
drop in production per breeding pair in 1954; and that in 1955 production got 
back to normal again. Thus it appears thatnesting data as well as brood data, 
can be used to indicate trends, and a forecast of the season's production can 
be made at least a month earlier from nesting data. This statement applies 
specifically to a study area but logically may be projected to a larger segment 
of country of which a given study area may be typical. 
Brood Averages 
Brood averages from the Redvers Study Area and from a radius of 
not more than 20 miles distant, follow in Table IX. 
Table IX. - Grood Averages by Age Classes. 
Class la Class III All Age Classes 
1952 1953 1954 1955 1952 1953 1954 1955 1952 1953 1954 1955 
Mallard 6.96 6.91 6,147.56 6.13 6.55 5.476.10 6.42 6.745.98 6.59 
B-w, Teal 8.87 8.50 8.888,95 7.25 7.98 8.838.45 7.94 8.21 8.66 8.54 
Fi ntail 6.40 7.12 4,507.25 5.005.19 4,185.50 5,62 5,82 4.38 6.50 
Baldpate 8.40 7.68 8,157.16 7.007.15 - 7.57 7.81 7.23 7.19 7,21 
Canvasback7,25 6.42 5.646.96 5.646.07 3.756.29 6.28 6.43 4.66 6.58 
Brood averages in general appear to be average for 1955 except for 
canvasback which showed a definite increase in nearly all age classes. Canvas- 
back data in 1955 is based on 267 broods and 1,757 individuals. 
