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We studied the relationship between temperature and the coexistence of great tit Parus major and blue tit Cyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.

* Secondary hole-nesting birds that do not construct nest holes themselves and hence regularly breed in nest boxes constitute important model systems for field studies in many biological disciplines with hundreds of scientists and amateurs involved. Those research groups are spread over wide geographic areas that experience considerable variation in environmental conditions, and researchers provide nest boxes of varying designs that may inadvertently introduce spatial and temporal variation in reproductive parameters. * We quantified the relationship between mean clutch size and nest box size and material after controlling for a range of environmental variables in four of the most widely used model species in the Western Palaearctic: great tit Parus major, blue tit Cyanistes caeruleus, pied flycatcher Ficedula hypoleuca and collared flycatcher F. albicollis from 365 populations and 79 610 clutches. * Nest floor area and nest box material varied non-randomly across latitudes and longitudes, showing that scientists did not adopt a random box design. Clutch size increased with nest floor area in great tits, but not in blue tits and flycatchers. Clutch size of blue tits was larger in wooden than in concrete nest boxes. * These findings demonstrate that the size of nest boxes and material used to construct nest boxes can differentially affect clutch size in different species. The findings also suggest that the nest box design may affect not only focal species, but also indirectly other species through the effects of nest box design on productivity and therefore potentially population density and hence interspecific competition. [KEYWORDS: geographic location habitat latitude longitude nest box floor area nest box material], * Secondary hole-nesting birds that do not construct nest holes themselves and hence regularly breed in nest boxes constitute important model systems for field studies in many biological disciplines with hundreds of scientists and amateurs involved. Those research groups are spread over wide geographic areas that experience considerable variation in environmental conditions, and researchers provide nest boxes of varying designs that may inadvertently introduce spatial and temporal variation in reproductive parameters. * We quantified the relationship between mean clutch size and nest box size and material after controlling for a range of environmental variables in four of the most widely used model species in the Western Palaearctic: great tit Parus major, blue tit Cyanistes caeruleus, pied flycatcher Ficedula hypoleuca and collared flycatcher F. albicollis from 365 populations and 79 610 clutches. * Nest floor area and nest box material varied non-randomly across latitudes and longitudes, showing that scientists did not adopt a random box design. Clutch size increased with nest floor area in great tits, but not in blue tits and flycatchers. Clutch size of blue tits was larger in wooden than in concrete nest boxes. * These findings demonstrate that the size of nest boxes and material used to construct nest boxes can differentially affect clutch size in different species. The findings also suggest that the nest box design may affect not only focal species, but also indirectly other species through the effects of nest box design on productivity and therefore potentially population density and hence interspecific competition. [KEYWORDS: geographic location habitat latitude longitude nest box floor area nest box material]

Red lists serve as the most prominent tool for priority setting in applied conservation, even though they were not originally designed for this task. Hence, threat status does not always reflect actual conservation needs and can be very different from actual conservation priorities. Therefore, red lists may at best be a suboptimal tool for setting conservation priorities in a country or region. As a response, a range of alternative or complementary tools have been developed, with approaches, methods, and parameters such as population decline, population center etc. used, differing widely among countries. One recent development is the combination of conservation status with a measure of the international importance of a population in a focal region for the global survival of a species. Here, we provide a new method that integrates the two concepts while keeping them conceptually separate. The main benefit of this method is that it can be applied across variable geographical scales such as regions, countries, and even continents. Furthermore, it allows for better recommendations for applied conservation and conservation policy development than the two concepts in isolation. Our method, if applied internationally, would allow for a standardized priority setting in species conservation, would be highly comparable between countries, and would lead to a more efficient use of the limited financial and human resources for monitoring and conservation of biodiversity.

The Convention on Biodiversity (CBD) commits its signatories to the identification and monitoring of biodiversity. The European Union has implemented this commitment into its legislation. Despite the legal requirement resources are scarce, requiring a prioritization of conservation actions, including e.g. monitoring. Red lists are currently the most prominent tool for priority setting in applied conservation, despite the fact that they were not developed for that purpose. Therefore, it is hardly surprising that they do not always reflect actual conservation needs. As a response, the concept of national responsibility as a complementary tool was developed during the last two decades. The existing methods are country specific and mainly incomparable on an international scale. Here, we present a newly developed method, which is applicable to any taxonomic group, adjustable to different geographic scales, with little data requirements and clear categorizations. We apply the new method to over 1,000 species in several countries of different size and report on the applicability of our method and discuss problems that derive from the currently available data. Our method has several major advantages compared to currently available methods. It is applicable to any geographic range, allows automatization, given database availability, and is readily adjustable to future data improvements. It further has comparably low data demands by exploiting one of the most commonly available information on biodiversity, i.e. distribution maps. We believe that our method allows the allocation of the limited resources in nature conservation in the most sensible way, e.g. the sharing of monitoring duties, effectively selecting networks of protected areas, improving knowledge on biodiversity, and closing information gaps in many species groups.