Rapid temporal change in the expression and age-related information content of a sexually selected trait

The expression of sexual signals is often phenotypically plastic and also evolves rapidly. Few studies have considered the possibility that proximate determination - the pathway between genes and trait expression - may also be subject to both phenotypic plasticity and evolutionary change. We examined long-term patterns in size, condition- and age-dependence, repeatability and heritability of forehead patch size, a sexually selected plumage trait in male collared flycatchers. We also estimated survival and sexual selection on the phenotypic value of the trait. Forehead patch size linearly declined during the 15 years, probably due to the significantly negative survival selection. In addition, the expression of genetic variation for the ornament apparently underwent an age-limited change, which implies a change in the information content of the signal to receivers. The persistent lack of condition-dependence makes phenotypic plasticity an unlikely explanation to our results. This raises the possibility of a microevolutionary change of both expression and proximate determination during the study period

Support for a colleague

As collaborators of Anders Pape Møller, we were shocked and surprised to read that he was accused of data fabrication ("Ecologists roiled by misconduct case," G. Vogel, F. Proffitt, R. Stone, News of the Week, 30 Jan., p. 606). We have never had cause to be concerned about any aspect of our collaborations with Møller. He is an amazing scientist, and his great organizational skills are a model for how to be productive in the face of competing time demands. Most of us are capable of much more than we actually accomplish, but we lack the dedication and self-discipline to follow through like Anders Møller. This is the secret of his phenomenal effectiveness that has been so puzzling to the scientific community. His achievements may have caused negative responses from some of his competitors. We would like to see a full, objective, and independent inquiry into the allegations. Our experience tells us that Anders Møller has an exceptionally complete focus on any task at hand, be it fieldwork, data analysis, or paper writing; this, combined with more than a little natural talent, is sufficient to explain his exceptional productivity. We have worked with him on a variety of projects, including collecting data, sometimes under arduous conditions, and in all our dealings with him, his behavior has been beyond reproach. We would ask colleagues to restrain from further public condemnation until such time as any allegations have been proven beyond doubt

Risk taking by singing males

The distance at which an individual flees from a potential predator represents a measure of risk taking. If individuals are engaged in another activity that might affect fitness, trade-offs between the fitness benefits of flight and the other activity should determine the nearest distance of approach by a predator. In a comparative analysis of birds, flight distance represented a reliable measure of risk of predation by the sparrowhawk Accipiter nisus that increased with decreasing flight distance across species. To test the hypothesis that singing males adjusted their risk taking to the costs and benefits of early flight, we compared the flight distance of singing and nonsinging birds to an approaching human observing with a binocular. Singing birds on average fled at a greater distance than nonsinging birds, implying that singing birds took small risks. We used a standardized measure of difference in flight distance between singing and nonsinging individuals to investigate factors affecting interspecific variation in risk taking. Species that used more exposed song posts (sites used for singing) took smaller risks than species with less exposed song posts. Species that suffered from higher levels of parasitism as reflected by the prevalence of Plasmodium, but not by 3 other genera of blood parasites, took greater risks during singing compared with nonsinging activities. Likewise, species with high circulating levels of natural antibodies, and hence a history of natural selection caused by bacteria took relatively greater risks during singing than species with few natural antibodies. These findings suggest that risks taken by singing birds have been molded by natural and sexual selection, and that risk taking represents a compromise between the costs and benefits of flight from a potential predator

The design of artificial nestboxes for the study of secondary hole-nesting birds: A review of methodological inconsistencies and potential biases

The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines. Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents. However, when comparing results across study sites the use of nestboxes may also introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. However, the use of nestboxes may also introduce an unconsidered and potentially significant confounding variable due to differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained. Here we review to what extent the characteristics of artificial nestboxes (e.g. size, shape, construction material, colour) are documented in the ‘methods’ sections of publications involving hole-nesting passerine birds using natural or excavated cavities or artificial nestboxes for reproduction and roosting. Despite explicit previous recommendations that authors describe in detail the characteristics of the nestboxes used, we found that the description of nestbox characteristics in most recent publications remains poor and insufficient. We therefore list the types of descriptive data that should be included in the methods sections of relevant manuscripts and justify this by discussing how variation in nestbox characteristics can affect or confound conclusions from nestbox studies. We also propose several recommendations to improve the reliability and usefulness of research based on long-term studies of any secondary hole-nesting species using artificial nestboxes for breeding or roosting.