Low pathogenic avian influenza A viruses have a natural host reservoir in wild waterbirds and the potential to spread to other host species. Here we investigate the evolutionary, spatial and temporal dynamics of avian influenza A viruses in Eurasian wild birds. We use whole genome sequences collected as part of an intensive long-term Eurasian wild bird surveillance study and combine this genetic data with temporal and spatial information to explore the virus evolutionary dynamics. Frequent reassortment and co-circulating lineages were observed for all eight genomic RNA segments over time. There was no apparent species-specific effect on the diversity of the avian influenza A viruses. There was a spatial and temporal relationship between the Eurasian sequences and significant viral migration of avian influenza A viruses from West towards Central Asia. The observed viral migration patterns differed between segments. Further we discuss the challenges faced when analysing these surveillance and sequence data and the caveats to be borne in mind when drawing conclusions from the apparent results of such analyses.