Inadequacies in nestbox studies reporting — a review of problems

Problems in reporting results of the nestbox studies, apart from those covered by Lambrechts et al. (2010. Acta Ornithologica 45; 1-26), are discussed. The nestbox papers mostly fail to provide essential data on breeding densities, nest predation rates, occurrence of nest soaking, presence of ectoparasites and brood productivity. The fact that the nestbox plots constitute large scale, long lasting field experiments is usually not acknowledged, and the consequences of those experimental conditions for the external validity of results are not assessed. Unqualified inferences on the adaptive value of birds ecology and behaviour are often made. To remove these shortcomings, it is proposed that every nestbox study should include 1) detailed description of the types, sizes and distribution of breeding of boxes used, effectiveness of nest predation and flood prevention, breeding densities in the methods section and 2) provision of a separate paragraph(s) in the Discussion telling the reader 1) how conditions in the study area differed from the reference (tree holes) state; 2) what could be the impact of these modified conditions on the outcome of study and 3) what is external validity of the results.