Acrylic paint on Canson Mi-Teintes Drawing Paper.
Each duet was painted separately then put together in Photoshop.
From top to bottom:
Chesnut-breasted Mannikin (Lonchura castaneothorax) and White-headed Munia (Lonchura maja)
Black and yellow Broadbill (Eurylaimus ochromalus) and Mindanao Wattled Broadbill (Eurylaimus steerii)
Black-throated Wattle-eye (Platysteira peltata) and Brown-throated Wattle-eye (Platysteira cyanea)