data indicate that, until the time they left their parents, young mallards 
suffered a mortality of about 20 per cent. 
Table 26.<-Reproductive Success of North American Mallards—III 
Data classified (where possible) according to size of young in broods 
IT IIT 
Class Nowy Younes 1/2 to 2/3 Grom About Ready to Fl 
Number Total Mean mber [ote Mean No. Total Mean 
Where Observed of Number No. per| of Number No. per of No. o.per 
_ |Broods Young Brood |Broods Young Brood | Broods Young Broo 
Alberta | 
(Smith 1948) | 33 231 =7.0 28 186 6.6 9 5S 6.1 
Saskatchewan | 
(Lynch 1948) , 3h 250 Te 36 2h2 = 6.7 7 60 8.6 
Saskatchewan | 1/ 1/ : 1/ 
No. Dakota | 
(Hammond 1948) 
No. Dakota | 
(Stoudt and 
Davis 1948) ' 7 6/9. 5 3 761 7 so 7 
Subtotal 12 808 Te2 121 797 6.6 52 403 7.8 
ee eee letetetetateteeetate seh are Bt tyes be AD) Ac ORE ce ae! 
| 
Minnesota 
1937-1 | 
(Stoudt 1946) 110 880 8.0 227 1702 7-5 | 252 1764 47.0 
1946 
(Stoudt 1918) 8  622/ 7.8 | 32 230 7.2 | 27 1892/ 7.0 
19448 
(Stoudt and 
Davis 1948) 7 50 71 43 3281/ 7.6 | se 356 6.8 
Subtotal 125 992 79 302 2260 7.5 331 2309 7.0 
28 192 6.9 29 175 6.0 9 7% 8.h 
Total 237 1800 7.6 423 3057 72 383. 2712 ~=7.1 
, computed from other statistics furnished by the author 
The age ratio at this early point in the cycle would appear 
to be about 7 young per successful female. The percentage of unsuc- 
cessful females in the population has yet to be ascertained, Some 
clues given by Kalmbach (1938) make a crude guess possible. Kalmbach 
divided the nesting season into halves and found thate-for all species of 
ducks--nests in the first half were 57 per cent successful, those in the 
_ second half 79 per cent successful. He believed that these latter nests | 
represented renesting attempts. If most of the 3. per cent of the hens 
(that failed the first time) actually renested, it would follow that 
6k 
