Evaluating estimators for numbers of females with cubs-of-the-year in the Yellowstone grizzly bear population

Journal of Agricultural, Biological, and Environmental Statistics
By: , and 

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Abstract

Current management of the grizzly bear (Ursus arctos) population in Yellowstone National Park and surrounding areas requires annual estimation of the number of adult female bears with cubs-of-the-year. We examined the performance of nine estimators of population size via simulation. Data were simulated using two methods for different combinations of population size, sample size, and coefficient of variation of individual sighting probabilities. We show that the coefficient of variation does not, by itself, adequately describe the effects of capture heterogeneity, because two different distributions of capture probabilities can have the same coefficient of variation. All estimators produced biased estimates of population size with bias decreasing as effort increased. Based on the simulation results we recommend the Chao estimator for model M h be used to estimate the number of female bears with cubs of the year; however, the estimator of Chao and Shen may also be useful depending on the goals of the research.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Evaluating estimators for numbers of females with cubs-of-the-year in the Yellowstone grizzly bear population
Series title Journal of Agricultural, Biological, and Environmental Statistics
Volume 12
Issue 2
Year Published 2007
Language English
Publisher American Statistical Association and the International Biometric Society
Contributing office(s) Northern Rocky Mountain Science Center
Description 21 p.
First page 195
Last page 215
Country United States
State Wyoming
Other Geospatial Yellowstone National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N
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