APPROXIMATING VARIANCE OF DEMOGRAPHIC PARAMETERS USING THE DELTA METHOD: A REFERENCE FOR AVIAN BIOLOGISTS

Avian biologists routinely estimate sampling variance for parameter estimates such as daily nest survival, fecundity, annual survival, and density. However, many biologists are not certain of methods to derive sampling variance for parameters when survival rates change temporal scales. Similar metho...

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Bibliographic Details
Published in:The Condor (Los Angeles, Calif.) Calif.), 2007-11, Vol.109 (4), p.949-954
Main Author: POWELL, LARKIN A
Format: Article
Language:English
Subjects:
Animal populations
Approximation
Biologists
Biology
Bird nesting
Birds
delta method
demographic analyses
Demographics
Demography
Density estimation
Estimation methods
Mathematical independent variables
Ornithology
Partial derivatives
Population estimates
sampling variance approximation
SHORT COMMUNICATIONS
Statistical variance
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Summary:Avian biologists routinely estimate sampling variance for parameter estimates such as daily nest survival, fecundity, annual survival, and density. However, many biologists are not certain of methods to derive sampling variance for parameters when survival rates change temporal scales. Similar methods are needed to obtain sampling variance when biologists combine parameter estimates to calculate an indirect demographic parameter, such as population growth rate. The delta method is a useful technique for approximating sampling variance when the desired demographic parameter is a function of at least one other demographic parameter. However, the delta method is rarely taught in most graduate-level biology or ecology courses, and application of this method may be discouraged by seemingly daunting formulas in reference books. Here, I provide five examples of sampling variance approximations for common situations encountered by avian ecologists, with step-by-step explanations of the equations involved.
ISSN:0010-5422
1938-5129
2732-4621
DOI:10.1650/0010-5422(2007)109[949:AVODPU]2.0.CO;2