The Composite Dynamic Method as Evidence for Age-Specific Waterfowl Mortality

Abstract

For the past 25 years estimation of mortality rates for waterfowl has been based almost entirely on the composite dynamic life table. We examined the specific assumptions for this method and derived a valid goodness of fit test. We performed this test on 45 data sets representing a cross section of banded samples for various waterfowl species, geographic areas, banding periods, and age/sex classes. We found that: (1) the composite dynamic method was rejected (P k, Si = 1 Mi = Annual survival rate (probability) for birds of age i, Mi = 1 S, = Annual mortality rate (probability) for birds of age i, fi = Annual band recovery rate (probability) for birds of age i, Ni = Number of birds banded in year i, i = 1, . . .,k, R, = Number of birds recovered in year j from birds banded in year i, i = 1,)..., k, j = 1, . . ., 1, Ri. = Total number of band recoveries from the ith banded cohort (i.e., birds banded in year i)