On Calculating Demographic Parameters from Age Frequency Data
1980
Michod, Richard E. | Anderson, Wyatt W.
Caughley and Birch (1971) showed that the usual method for calculating age—specific longevities from the age distribution of living animals, mammals in particular, has built into it the assumption that r = 0. Consequently a set of lᵢ's calculated this way could not in turn be used with a table of fecundities to predict r. We show that when both the frequencies and fecundities of the age classes are known, provided that the fecundities correspond to what Leslie (1945) termed Fᵢ, the assumption that r = 0. is unnecessary. It is a sample matter to calculate not only the lᵢ but r as well, assuming only a stable age structure. Formulas for doing so are given and applied, as an example, to data on the grey fox.
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