The composite dynamic method as evidence for age-specific waterfowl mortality

Journal of Wildlife Management
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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 sampled for various waterfowl species, geographic areas, banding periods, and age/sex classes. We found that: (1) the composite dynamic method was rejected (P <0.001) in 37 of the 45 data sets (in fact, 29 were rejected at P <0.00001) and (2) recovery and harvest rates are year-specific (a critical violation of the necessary assumptions). We conclude that the restrictive assumptions required for the composite dynamic method to produce valid estimates of mortality rates are not met in waterfowl data. Also we demonstrate that even when the required assumptions are met, the method produces very biased estimates of age-specific mortality rates. We believe the composite dynamic method should not be used in the analysis of waterfowl banding data. Furthermore, the composite dynamic method does not provide valid evidence for age-specific mortality rates in waterfowl.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title The composite dynamic method as evidence for age-specific waterfowl mortality
Series title Journal of Wildlife Management
DOI 10.2307/3800344
Volume 43
Issue 2
Year Published 1979
Language English
Publisher Wildlife Society
Publisher location Washington, D.C.
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Journal of Wildlife Management
First page 356
Last page 366