Estimation of tiger population total through pugmark measurements:Some answered and unanswered questions

Mary Woodcock Kroble
Thursday 9 November 2006
Date: 28 June 2007
Time: 4:00 pm - 5:00 pm

Speaker: Debasis Sengupta (Indian Statistical Institute, Kolkata)


The problem of estimating population total of tigers from pugmark measurements poses a number of interesting statistical questions that are not addressed through conventional methods of estimating animal abundance. Unlike elephants producing dung or birds producing nest, tigers do not produce pugmarks at a uniform rate. On the other hand, pugmarks do not carry as accurate and reliable information as fingerprints do. Is it still possible to estimate the population total precisely and accurately? If so, what should be the appropriate number of pugmarks to be collected? Which features of a pugmark carry useful information for discrimination? How can one cluster the pugmarks so that each group of pugmarks belongs to a distinct tiger? Is good clustering a prerequisite for good estimation of population total? Is it possible to account for tigers missed in the sample? How can one utilize positional information for tiger counting? How wide are confidence intervals for the population total? How can the estimation be improved? In this talk, I shall present the currently available answers to these questions, and identify areas where further investigation is needed.

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