Recovery and survival rates and geographic distributions of recoveries were compared for adult and subadult mallards (Anas platyrhynchos) banded postseason in eastern Colorado [USA] during the period 1963 through 1972. Almost 4400 recoveries from over 51,000 bandings were analyzed. Mean recovery rates were equal for adult and subadult males (3.7%), and for adult and subadult females (1.8% and 2.1%, respectively). Mean survival rates were also nearly equal between the 2 age classes of each sex, about 76% for males and 69% for females. A much higher proportion of the total 1st yr recoveries of adult males (66%) and adult females (50%) occurred in eastern Colorado than that for subadult males (43%) and subadult females (31%). Additional comparisons of these population parameters by age class should be made for population segments of mallards in other wintering areas to see if the results obtained in eastern Colorado apply over a broader area. This would require the aging of birds during postseason banding.