Baldwin-Phillips-Terlevich (BPT) classification diagram for GRB hosts. The background sample is the logarithmic space density of local (z ~ 0) SDSS galaxies with line-fluxes from the MPA/JHU catalog¹¹. Colored circles are 34 individual GRB-selected galaxies with redshifts indicated by the color bar. The increasingly darker dashed gray lines are the redshift-dependent differentiation lines between star-forming galaxies and AGN of Kewley et al. (2013b) at the indicated redshifts. The black solid line is the ridge line, i.e., the line with the highest density of SDSS galaxies. Dusty/normal GRBs are indicated by stars/circles.