Effect of Investigator Disturbance on Hatching Success in Endangered Takahe

Ian Jamieson

The Takahe is a flightless New Zealand bird thought to be extinct until discovered in 1948. A management programme was introduced by the Department of Conservation to increase numbers. This lesson investigates whether nest monitoring affects nesting success.



The data are presented in the Excel file TakaheDataAndVariables.xls.

The small samples and type of data make it necessary to use non parametric procedures for analyzing the data discussed in this study rather than a matched or paired data t-test. The non parametric tests are not in the New Zealand school syllabus but the discussion about the design of this study and interpretation of results contain worthwhile ideas.

  • Task 1: Check the hatching success, fertility and fecundity percentages for the Disturbed and Non Disturbed nests. Compare the differences in percentages by carrying out a non parametric Wilcoxon matched pairs test on the proportions (rather than a parametric paired t-test).
  • Task 2: Calculate the mean numbers of hatched eggs for the Non disturbed and Disturbed nests with 95% confidence intervals. You may consider the bootstrap procedure.

If you have access to GenStat, you can go through the lesson Takahe-GenStat.pdf.

Video content recorded and edited by Robert van der Vyver[1] and John Harraway[2].
Web site developed and maintained by Greg Trounson[2] and John Harraway
Contact us

1: Higher Education Development Unit, University of Otago
2: Department of Mathematics and Statistics, University of Otago