The electronic noise properties of Si-doped AlN and Al0.3Ga0.7N are investigated. In AlN : Si, generation–recombination (g–r) noise is observed and shown to be linked to DX-centers. The potential energy barriers for capture into and emission from the DX− ground state are quantitatively determined from the noise measurements. In Al0.3Ga0.7N:Si, in addition to 1/f noise, we find two g–r noise processes. However, an unambiguous identification of their origin proves to be difficult.