Table 42. Reduction of brood size of 12 duck species between age classes for July and August counts, Woodworth Study Area, 1965-81. |
Reduction of brood size from average age Class I to Class III ducklings | ||
Species | Number | Percent |
Dabbling ducks | ||
Mallard | 0.5 | 8 |
Gadwall | 0.3a | 4a |
American wigeon | 1.3 | 18 |
Green-winged teal | 1.5 | 27 |
Blue-winged teal | 1.0 | 14 |
Northern shoveler | 0.8 | 14 |
Northern pintail | 2.8 | 42 |
Total dabbling ducks | 1.2 | 17 |
Diving ducks | ||
Redhead | 2.9 | 44 |
Canvasback | 2.0 | 37 |
Lesser scaup | 0.9b | 13b |
Ring-necked duck | 2.0b | 33b |
Ruddy duck | 0.6b | 12b |
Total diving ducks | 1.5 | 25 |
All broods | 1.1 | 16 |
aBased on Class II brood
size because of no sample of Class III broods. bAverage brood size increased between Classes I and II; no sample of Class III broods. |