Table 29.--Mortality in Adult North American Mallards That Were 
Unaged When Banded 
Each age starts as of September 1; game~farm birds and those suffer- 
ing from botulism when trapped were excluded. Not all the records 
included here could be checked against the banders' original reports. 
The Pacific coast birds were all males; x means additional reports 
can be expected. 
Mortality ot ve Mo y 
Where Banded.....-MO. = ‘ ac. Coas Nurber at Rate 




When Banded. ..oee. 1922-28 1926-35 Dead Start _ (per cent 
Age Interval (Yrs) Each Age per annum) 
X+1ltox+ 2 578 99 1527 2992 51.0 
x+2 tox + 3 333 376 709 1465 48.h 
X+3tox+h 135 170 305 756 0 
x+htox¢S5 7h 110 18); 451 1 
x+¢5 tox +6 50 66 116 267 43 
xXx+6tox+ 7 26 12 68 151 LS | 
x+7tox+ 8 lk 17 31 83 
x~~ 6 tox +9 11 15 — 26 52 
x+9 to x +10 5 7 12 26 
Xx410 ta x 311 3 6 9 ly 
x +11 to x +12 0 \ h 5 Ths 
x +12 to x + 13 0 x (0) 1 
x +13 to x 4.14 0 x 5 1 
x + lh tox +15 0 x (O 1 
x +15 to x + 16 1 x (1) 1 
Total 1230 1762 2992 4 =—6 © 266 — 
Mean Mort. Rate 6.5% 48.5% = - 7.7 



The mean of 7.7 per cent is among the first approximations 
(Bellrose and Chase 1950; Hanson and Smith 1950) we have for a water- 
fowl's adult mortality rate on this continent. The sample covers a 
period during the 1930's when ducks were decreasing in North America. | 
Drought in itself might not affect the adult mortality rate of such 
mobile animals, but the tightening up of hunting regulations (which 
paralleled the drought) presumably would. Further analysis of such 
factors is pursued in Part III of this study. 
seme ere reports.-=For about every 100 hunters 
reporting, one mammal trapper has caught a banded mallard in traps 
usually set for mskrats. Unless some mallard behavior trait 
associated with age influences this phenomenon, banding samples so 
gathered are a pertinent check on survival calculated from hunting 
mortality. The data are not specific for age and the samples very 
small, but they should reflect approximately correct rates of annual 
survival in adults, I found that the dates of capture by fur trappers 
ran from August to April (inclusive), with a major frequency peak in 
November and a minor peak in March. About two-thirds of the reports 
came from Canada; the rest were spread over 2); states in the United 
70 
