Distribution of our targets in redshift (left) and radio power (right). In both panels, the red solid and dark green hatched histograms show our sample and the parent sample of all known powerful radio galaxies at z ≥ 2 from Miley & De Breuck (2008), respectively. The gap between z = 2.6 and z = 2.9 in the left panel is because no bright optical emission lines fall into the near-infrared atmospheric windows at these redshifts. The light blue and light red lines in the right panel show the luminosity function of powerful radio galaxies at redshifts z = 0 and z = 2 from Willott et al. (2001), respectively. The dot-dashed light red line highlights their high-power “high-z” population (for details see Willott et al. 2001).