Strains differing by at least one nucleotide were downloaded from GenBank (access date 29th of September of 2015) resulting in 66 P4b strains including the two strains found in house sparrows in this study. The most appropriate nucleotide substitution model was found under a Bayesian information criterion with PartitionFinder : HKY+I+G. We inferred the phylogenetic relationships with a Bayesian analysis using BEAST 2.0  after setting the parameters for the BEAST-run in BEAUTI 2.0 . Markov Monte Carlo Chains (MCMC’s) were run for 109 generations sampling every 10,000 trees using a Yule speciation prior and an estimated molecular strict clock since our data could not reject this model based on the underlying log normal distribution standard deviation (ucld.stdev) values histogram in Tracer v1.5 (http://tree.bio.ed.ac.uk/software/tracer/). All estimated sample sizes were higher than 200 and the resulting 100.000 trees were summarized in TreeAnnotator v2.1.2 (http://beast.bio.ed.ac.uk/treeannotator) after removing a 25% burn-in and are displayed in Figtree v1.4.2 (http://tree.bio.ed.ac.uk/software/figtree/).