Acute infections can alter foraging and movement behaviours relevant to sociality and pathogen spread. However, few studies have examined how infection with directly-transmitted pathogens influences host social preferences. Juvenile house finches are gregarious and particularly susceptible to infection by the bacterial pathogen Mycoplasma gallisepticum (MG). Changes in sociality during infection are likely to have important consequences for MG transmission throughout majority-juvenile flocks, but it remains unknown how infection influences sociality in house finches. To test this, we inoculated 33 wild-caught juvenile house finches with MG or media (sham control). At peak infection, birds were given a choice assay to assess preference for associating near a flock versus an empty cage. Infected birds were significantly more likely than controls to spend time near the flock while eating, and marginally so while perching. These results indicate augmented social preferences during infection, potentially as a form of behavioural tolerance. Notably, infected birds showed strong social preferences regardless of individual variation in disease severity or pathogen loads, with 14/19 harbouring high loads (log10 5-6) at time of assay. Overall, our results show that infection with a directly-transmitted pathogen can augment social preferences, with potential implications for MG spread in natural populations.

This dataset was collected from behavioural experiments on live birds. All data is provided in the file "Inf_Social.csv". All data was processed and analysed using RStudio. R Code is provided in the document "Langager_Sociality_Code.R".

All variables used for analysis are annotated and described in the R code.