  We present 5.5 and 9.0 GHz observations of a sample of seventeen GRB host
galaxies at 0.5<z<1.4, using the radio continuum to explore their star
formation properties in the context of the small but growing sample of galaxies
with similar observations. Four sources are detected, one of those (GRB
100418A) likely due to lingering afterglow emission. We suggest that the
previously-reported radio afterglow of GRB 100621A may instead be due to host
galaxy flux. We see no strong evidence for redshift evolution in the typical
star formation rate of GRB hosts, but note that the fraction of `dark' bursts
with detections is higher than would be expected given constraints on the more
typical long GRB population. We also determine the average radio-derived star
formation rates of core collapse supernovae at comparable redshift, and show
that these are still well below the limits obtained for GRB hosts, and show
evidence for a rise in typical star formation rate with redshift in supernova
hosts.
