Is recreation affecting the number of birds' nests? A case study

This paper presents some results arising out of the collaboration during 1974–1980 between an ornithologist (the first author) and a statistician. Attention is focussed on the question as to whether Tables 1 and 2 provide sufficient evidence for the existence of effects of recreation upon the numbers of oyster‐catcher nests and on the estimation of these effects by means of confidence intervals. The main tool is the standard theory for constructing conditional tests for multiparameter exponential families. The authors try to give a very careful description of the methodological aspects of their case. Many different probabilistic models can be proposed. Accordingly the statistical problems concerning tests and confidence intervals admit different mathematical formulations and (or) solutions. It is now apparent that, during their collaboration, the authors did not always make the most appropriate choice of models and procedures. They went through several stages before arriving at the choices which are basic to the sections 2, …, 5. By outlining these stages in Section 6 and mentioning the methodological errors which were committed they hope that readers will beware of similar pitfalls.