THE CONTRIBUTION OF ARTIFICIAL NEST EXPERIMENTS TO UNDERSTANDING AVIAN REPRODUCTIVE SUCCESS - A REVIEW OF METHODS AND CONCLUSIONS

Artificial nest experiments have been used in approximately 80 recent studies to identify a wide range of factors influencing reproductive s uccess of birds. Despite the same factors being examined in different studies, few consistent patterns have emerged from these experiments. Analysis of reproductive success at artificial and natural nests revea ls that reproductive success measured with use of artificial nests is frequently underestimated, In addition, several studies suggest that d ifferent species of predators may be differentially attracted to the t wo types of nest. These results call the utility of artificial nests i nto question as a tool for elucidating factors influencing the success of natural nests, Analysis of the methodology used in artificial nest experiments reveals that in general there is poor correspondence betw een the appearance of experimental setups and the natural systems they attempt to model. If future experiments with artificial nests are to contribute to theory, the quality of experiments must improve and the assumptions underlying the artificial approach must be tested, Collect ing this information will be relatively simple compared with the time- consuming task of experimenting with natural nests, Until these data a re collected, conclusions about nesting ecology derived from the use o f artificial nest experiments should be treated as preliminary.