Demographic Analysis from Summaries of an Age-Structured Population
Article first published online: 11 DEC 2003
Volume 59, Issue 4, pages 778–785, December 2003
How to Cite
Link, W. A., Royle, J. A. and Hatfield, J. S. (2003), Demographic Analysis from Summaries of an Age-Structured Population. Biometrics, 59: 778–785. doi: 10.1111/j.0006-341X.2003.00091.x
- Issue published online: 11 DEC 2003
- Article first published online: 11 DEC 2003
- Received July 2002. Revised June 2003. Accepted June 2003.
- Age-structured populations;
- Demographic analysis;
- Latent variables;
- Markov chain Monte Carlo;
- Whooping cranes;
- Wildlife statistics
Summary. Demographic analyses of age-structured populations typically rely on life history data for individuals, or when individual animals are not identified, on information about the numbers of individuals in each age class through time. While it is usually difficult to determine the age class of a randomly encountered individual, it is often the case that the individual can be readily and reliably assigned to one of a set of age classes. For example, it is often possible to distinguish first-year from older birds. In such cases, the population age structure can be regarded as a latent variable governed by a process prior, and the data as summaries of this latent structure. In this article, we consider the problem of uncovering the latent structure and estimating process parameters from summaries of age class information. We present a demographic analysis for the critically endangered migratory population of whooping cranes (Grus americana), based only on counts of first-year birds and of older birds. We estimate age and year-specific survival rates. We address the controversial issue of whether management action on the breeding grounds has influenced recruitment, relating recruitment rates to the number of seventh-year and older birds, and examining the pattern of variation through time in this rate.