Mean flight distances (with standard deviations) calculated from the 450 bee re-sightings shown in Suppl. material 2: Table S1, with year of observation given for Osmia cornuta, studied in both 2017 and 2018. All remaining data are from 2017. Species body sizes are from Amiet et al. (2004) and Scheuchl (2006). For the smaller species Chelostoma florisomne, C. rapunculi, and Heriades truncorum, which were colour-tagged rather than number-tagged, we cannot exclude repeated observations of the same individual.