Colour-magnitude diagram of dwarf galaxies within the ∼2.5 × 4 deg² area shown in Fig. 2. Circles show the LTDs and crosses are the ETDs. The dwarfs detected in H I have been labelled and coloured by their M_HI. The LTDs with H I are shown as filled circles and the ETDs with H I are the thick crosses. The LTDs with disturbed H I morphologies are enclosed by dashed circles. The solid blue line separates the blue cloud from the red sequence. As expected, the bluer, brighter LTDs have a higher M_HI.