Background All over Europe, ordinary citizens, especially bird watchers, are increasingly contributing to the provision of up-to-date, reliable and policy-relevant data on nature and biodiversity. The vast amount of data collected through the existing online bird portals offers great potential for understanding the temporal and spatial distribution of birds across large areas. Aggregating the existing datasets at EU level in an effective and policy-relevant way is highly desirable and would be of high added value for EU biodiversity policy (in particular Habitat and Bird Directives), but several challenges must be overcome. A prototype EuroBirdPortal (EBP) was recently developed. It is a common data repository with a demonstration viewer that allows species-specific animated maps of bird migration over Europe to be displayed for the first time. It holds data from each of the existing online bird systems in Europe, but further improvements and adjustments are needed to increase the value, reliability and relevance of this tool throughout the entire EU. Objectives The aim of this project is to develop the existing EuroBirdPortal (EBP) demo viewer into a full-fledged web portal displaying reliable Europe-wide patterns of bird distribution in near real time. The specific objectives are to: Create a new EBP data sharing standard, database repository and data-flow system capable of managing automatically and in near-real-time all data interchange processes between the local online portals and the central databank; Adapt and improve the current EBP demo viewer and the spatial bird distribution models in order to reliably display detailed and up-to-date Europe-wide spatiotemporal patterns of bird distribution in near real time; Increase the geographical coverage of the EBP project to include most of the European Union (more than 90% of its territory); and Improve the quality and relevance of the data collected. A complementary objective is to promote ‘citizen science data collection’ on an EU-wide scale; this project is expected to provide a best practice example for compiling and displaying citizen science information on a European level. Expected results: The data flow of 12 online systems or, at least, the equivalent to more than 80% of all data collected by EBP partners are automatically connected to the new database repository using the new data sharing standard; The EBP viewer depicts the whole geographic area covered by the project, and includes 100 bird species and ‘average’ maps; The EBP viewer content is updated at weekly intervals and incorporates the new spatiotemporal models of bird distribution; The area covered by the EBP project includes at least 90% of the EU territory; Two reference documents – one on best practices and one on portals quality indicators and benchmarks – are produced; The actions directed to improve data quality and relevance produce an overall significant increase in the percentage of observations submitted to the central database included in complete lists (>10%) and a reduction of 20% of the areas identified as ‘poorly surveyed’; and At least two trials combining EBP data with other sources of bird movement and connectivity information are conducted.